Struct spinoso_string::String

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pub struct String { /* private fields */ }

Implementations§

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impl String

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pub fn new() -> Self

Constructs a new, empty String.

The String is conventionally UTF-8.

The string will not allocate until bytes are pushed onto it.

Examples
use spinoso_string::{Encoding, String};

let s = String::new();
assert_eq!(s.encoding(), Encoding::Utf8);
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pub fn with_capacity(capacity: usize) -> Self

Constructs a new, empty String with the specified capacity.

The String is conventionally UTF-8.

The string will be able to hold at least capacity bytes without reallocating. If capacity is 0, the string will not allocate.

It is important to note that although the returned string has the capacity specified, the string will have a zero length. For an explanation of the difference between length and capacity, see Capacity and reallocation.

Examples

Encoding, capacity, and length:

use spinoso_string::{Encoding, String};

let s = String::with_capacity(10);
assert_eq!(s.encoding(), Encoding::Utf8);
assert!(s.capacity() >= 10);
assert_eq!(s.len(), 0);

Allocation:

use spinoso_string::{Encoding, String};

let mut s = String::with_capacity(10);

for ch in 'a'..='j' {
    s.push_byte(ch as u8);
}
// 10 elements have been inserted without reallocating.
assert!(s.capacity() >= 10);
assert_eq!(s.len(), 10);
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pub fn with_capacity_and_encoding(capacity: usize, encoding: Encoding) -> Self

Constructs a new, empty String with the specified capacity and encoding.

The string will be able to hold at least capacity bytes without reallocating. If capacity is 0, the string will not allocate.

It is important to note that although the returned string has the capacity specified, the string will have a zero length. For an explanation of the difference between length and capacity, see Capacity and reallocation.

Examples

Encoding, capacity, and length:

use spinoso_string::{Encoding, String};

let s = String::with_capacity(10);
assert_eq!(s.encoding(), Encoding::Utf8);
assert!(s.capacity() >= 10);
assert_eq!(s.len(), 0);

Allocation:

use spinoso_string::{Encoding, String};

let mut s = String::with_capacity_and_encoding(10, Encoding::Binary);
assert_eq!(s.encoding(), Encoding::Binary);

for ch in 'a'..='j' {
    s.push_byte(ch as u8);
}
// 10 elements have been inserted without reallocating.
assert!(s.capacity() >= 10);
assert_eq!(s.len(), 10);
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pub fn with_bytes_and_encoding(buf: Vec<u8>, encoding: Encoding) -> Self

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pub fn utf8(buf: Vec<u8>) -> Self

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pub fn ascii(buf: Vec<u8>) -> Self

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pub fn binary(buf: Vec<u8>) -> Self

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impl String

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pub fn encoding(&self) -> Encoding

Returns the Encoding of this String.

Examples
use spinoso_string::{Encoding, String};

let s = String::utf8(b"xyz".to_vec());
assert_eq!(s.encoding(), Encoding::Utf8);
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pub fn set_encoding(&mut self, encoding: Encoding)

Set the Encoding of this String.

Examples
use spinoso_string::{Encoding, String};

let mut s = String::utf8(b"xyz".to_vec());
assert_eq!(s.encoding(), Encoding::Utf8);
s.set_encoding(Encoding::Binary);
assert_eq!(s.encoding(), Encoding::Binary);
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pub fn truncate(&mut self, len: usize)

Shortens the string, keeping the first len bytes and dropping the rest.

If len is greater than the string’s current length, this has no effect.

Note that this method has no effect on the allocated capacity of the string.

Examples

Truncating a five byte to two elements:

use spinoso_string::String;

let mut s = String::from("12345");
s.truncate(2);
assert_eq!(*s, *b"12");

No truncation occurs when len is greater than the string’s current length:

use spinoso_string::String;

let mut s = String::from("12345");
s.truncate(10);
assert_eq!(*s, *b"12345");

Truncating when len == 0 is equivalent to calling the clear method.

use spinoso_string::String;

let mut s = String::from("12345");
s.truncate(0);
assert_eq!(*s, *b"");
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pub fn as_slice(&self) -> &[u8]

Extracts a slice containing the entire byte string.

Equivalent to &s[..].

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pub fn as_mut_slice(&mut self) -> &mut [u8]

Extracts a mutable slice containing the entire byte string.

Equivalent to &mut s[..].

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pub fn as_ptr(&self) -> *const u8

Returns a raw pointer to the string’s buffer.

The caller must ensure that the string outlives the pointer this function returns, or else it will end up pointing to garbage. Modifying the string may cause its buffer to be reallocated, which would also make any pointers to it invalid.

The caller must also ensure that the memory the pointer (non-transitively) points to is never written to (except inside an UnsafeCell) using this pointer or any pointer derived from it. If you need to mutate the contents of the slice, use as_mut_ptr.

Examples
use spinoso_string::String;

let s = String::utf8(b"xyz".to_vec());
let s_ptr = s.as_ptr();

unsafe {
    for i in 0..s.len() {
        assert_eq!(*s_ptr.add(i), b'x' + (i as u8));
    }
}
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pub fn as_mut_ptr(&mut self) -> *mut u8

Returns an unsafe mutable pointer to the string’s buffer.

The caller must ensure that the string outlives the pointer this function returns, or else it will end up pointing to garbage. Modifying the string may cause its buffer to be reallocated, which would also make any pointers to it invalid.

Examples
use spinoso_string::String;

// Allocate string big enough for 3 bytes.
let size = 3;
let mut s = String::with_capacity(size);
let s_ptr = s.as_mut_ptr();

// Initialize elements via raw pointer writes, then set length.
unsafe {
    for i in 0..size {
        *s_ptr.add(i) = b'x' + (i as u8);
    }
    s.set_len(size);
}
assert_eq!(&*s, b"xyz");
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pub unsafe fn set_len(&mut self, new_len: usize)

Forces the length of the string to new_len.

This is a low-level operation that maintains none of the normal invariants of the type. Normally changing the length of a string is done using one of the safe operations instead, such as truncate, extend, or clear.

This function can change the return value of String::is_valid_encoding.

Safety
  • new_len must be less than or equal to capacity().
  • The elements at old_len..new_len must be initialized.
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pub unsafe fn from_raw_parts(raw_parts: RawParts<u8>) -> Self

Creates a String directly from the raw components of another string.

Safety

This is highly unsafe, due to the number of invariants that aren’t checked:

  • ptr needs to have been previously allocated via String (at least, it’s highly likely to be incorrect if it wasn’t).
  • length needs to be less than or equal to capacity.
  • capacity needs to be the capacity that the pointer was allocated with.

Violating these may cause problems like corrupting the allocator’s internal data structures.

The ownership of ptr is effectively transferred to the String which may then deallocate, reallocate or change the contents of memory pointed to by the pointer at will. Ensure that nothing else uses the pointer after calling this function.

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pub unsafe fn from_raw_parts_with_encoding(
    raw_parts: RawParts<u8>,
    encoding: Encoding
) -> Self

Creates a String directly from the raw components of another string with the specified encoding.

Safety

This is highly unsafe, due to the number of invariants that aren’t checked:

  • ptr needs to have been previously allocated via String (at least, it’s highly likely to be incorrect if it wasn’t).
  • length needs to be less than or equal to capacity.
  • capacity needs to be the capacity that the pointer was allocated with.

Violating these may cause problems like corrupting the allocator’s internal data structures.

The ownership of ptr is effectively transferred to the String which may then deallocate, reallocate or change the contents of memory pointed to by the pointer at will. Ensure that nothing else uses the pointer after calling this function.

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pub fn into_raw_parts(self) -> RawParts<u8>

Decomposes a String into its raw components.

Returns the raw pointer to the underlying data, the length of the string (in bytes), and the allocated capacity of the data (in bytes). These are the same arguments in the same order as the arguments to from_raw_parts.

After calling this function, the caller is responsible for the memory previously managed by the String. The only way to do this is to convert the raw pointer, length, and capacity back into a String with the from_raw_parts function, allowing the destructor to perform the cleanup.

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pub fn into_vec(self) -> Vec<u8>

Converts self into a vector without clones or allocation.

This method consumes this String and returns its inner Vec<u8> buffer.

Examples
use spinoso_string::String;

let s = String::from("hello");
let buf = s.into_vec();
// `s` cannot be used anymore because it has been converted into `buf`.

assert_eq!(buf, b"hello".to_vec());
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pub fn into_boxed_slice(self) -> Box<[u8]>

Converts the vector into Box<[u8]>.

Note that this will drop any excess capacity.

Examples
use spinoso_string::String;

let s = String::from("abc");
let slice = s.into_boxed_slice();

Any excess capacity is removed:

use spinoso_string::String;

let mut s = String::with_capacity(10);
s.extend_from_slice(&[b'a', b'b', b'c']);

assert!(s.capacity() >= 10);
let slice = s.into_boxed_slice();
assert_eq!(slice.into_vec().capacity(), 3);
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pub fn capacity(&self) -> usize

Returns the number of bytes the string can hold without reallocating.

Examples
use spinoso_string::String;

let s = String::with_capacity(10);
assert!(s.capacity() >= 10);
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pub fn clear(&mut self)

Clears the string, removing all bytes.

Note that this method has no effect on the allocated capacity or the encoding of the string.

Examples
use spinoso_string::String;

let mut s = String::from("abc");
s.clear();
assert!(s.is_empty());
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pub fn is_empty(&self) -> bool

Returns true if the vector contains no bytes.

Examples
use spinoso_string::String;

let mut s = String::new();
assert!(s.is_empty());

s.push_char('x');
assert!(!s.is_empty());
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pub fn len(&self) -> usize

Returns the number of bytes in the string, also referred to as its “length” or “bytesize”.

See also bytesize.

Examples
use spinoso_string::String;

let s = String::from("xyz");
assert_eq!(s.len(), 3);
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impl String

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pub fn iter(&self) -> Iter<'_>

Returns an iterator over this string’s underlying byte slice.

Examples
use spinoso_string::String;

let s = String::from("abc");
let mut iterator = s.iter();

assert_eq!(iterator.next(), Some(&b'a'));
assert_eq!(iterator.next(), Some(&b'b'));
assert_eq!(iterator.next(), Some(&b'c'));
assert_eq!(iterator.next(), None);
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pub fn iter_mut(&mut self) -> IterMut<'_>

Returns an iterator that allows modifying this string’s underlying byte slice.

Examples
use spinoso_string::String;

let mut s = String::from("abc");

for byte in s.iter_mut() {
    *byte = b'x';
}

assert_eq!(s, "xxx");
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pub fn bytes(&self) -> Bytes<'_>

Returns an iterator over the bytes in this byte string.

Examples
use spinoso_string::String;

let s = String::utf8(b"foobar".to_vec());
let bytes: Vec<u8> = s.bytes().collect();
assert_eq!(bytes, s);
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impl String

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pub fn reserve(&mut self, additional: usize)

Reserves capacity for at least additional more bytes to be inserted in the given String. The string may reserve more space to avoid frequent reallocations. After calling reserve, capacity will be greater than or equal to self.len() + additional. Does nothing if capacity is already sufficient.

Panics

Panics if the new capacity exceeds isize::MAX bytes.

Examples
use spinoso_string::String;

let mut s = String::from("x");
s.reserve(10);
assert!(s.capacity() >= 11);
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pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError>

Tries to reserve capacity for at least additional more elements to be inserted in the String. The collection may reserve more space to avoid frequent reallocations. After calling try_reserve, capacity will be greater than or equal to self.len() + additional. Does nothing if capacity is already sufficient.

Errors

If the capacity overflows, or the allocator reports a failure, then an error is returned.

Examples
use spinoso_string::String;
let mut str = String::from("x");
str.try_reserve(10).expect("why is this OOMing?");
assert!(str.capacity() >= 11);
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pub fn reserve_exact(&mut self, additional: usize)

Reserves the minimum capacity for exactly additional more bytes to be inserted in the given String. After calling reserve_exact, capacity will be greater than or equal to self.len() + additional. Does nothing if the capacity is already sufficient.

Note that the allocator may give the string more space than it requests. Therefore, capacity can not be relied upon to be precisely minimal. Prefer reserve if future insertions are expected.

Panics

Panics if the new capacity exceeds isize::MAX bytes.

Examples
use spinoso_string::String;

let mut s = String::from("x");
s.reserve_exact(10);
assert!(s.capacity() >= 11);
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pub fn try_reserve_exact(
    &mut self,
    additional: usize
) -> Result<(), TryReserveError>

Tries to reserve the minimum capacity for exactly additional elements to be inserted in the String. After calling try_reserve_exact, capacity will be greater than or equal to self.len() + additional if it returns Ok(()). Does nothing if the capacity is already sufficient.

Note that the allocator may give the collection more space than it requests. Therefore, capacity can not be relied upon to be precisely minimal. Prefer try_reserve if future insertions are expected.

Errors

If the capacity overflows, or the allocator reports a failure, then an error is returned.

Examples
use spinoso_string::String;
let mut str = String::from("x");
str.try_reserve_exact(10).expect("why is this OOMing?");
assert!(str.capacity() >= 11);
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pub fn shrink_to_fit(&mut self)

Shrinks the capacity of the vector as much as possible.

It will drop down as close as possible to the length but the allocator may still inform the string that there is space for a few more bytes.

Examples
use spinoso_string::String;

let mut s = String::with_capacity(10);
s.extend_from_slice(b"abc");
assert!(s.capacity() >= 10);
s.shrink_to_fit();
assert!(s.capacity() >= 3);
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pub fn shrink_to(&mut self, min_capacity: usize)

Shrinks the capacity of the vector with a lower bound.

The capacity will remain at least as large as both the length and the supplied value.

If the current capacity is less than the lower limit, this is a no-op.

Examples
use spinoso_string::String;

let mut s = String::with_capacity(10);
s.extend_from_slice(b"abc");
assert!(s.capacity() >= 10);
s.shrink_to(5);
assert!(s.capacity() >= 5);
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impl String

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pub fn get<I>(&self, index: I) -> Option<&I::Output>where
    I: SliceIndex<[u8]>,

Returns a reference to a byte or sub-byteslice depending on the type of index.

  • If given a position, returns a reference to the byte at that position or None if out of bounds.
  • If given a range, returns the subslice corresponding to that range, or None if out of bounds.
Examples
use spinoso_string::String;

let s = String::from("abc");
assert_eq!(s.get(1), Some(&b'b'));
assert_eq!(s.get(0..2), Some(&b"ab"[..]));
assert_eq!(s.get(3), None);
assert_eq!(s.get(0..4), None);
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pub fn get_mut<I>(&mut self, index: I) -> Option<&mut I::Output>where
    I: SliceIndex<[u8]>,

Returns a mutable reference to a byte or sub-byteslice depending on the type of index (see get) or None if the index is out of bounds.

Examples
use spinoso_string::String;

let mut s = String::from("abc");

if let Some(byte) = s.get_mut(1) {
    *byte = b'x';
}
assert_eq!(s, "axc");
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pub unsafe fn get_unchecked<I>(&self, index: I) -> &I::Outputwhere
    I: SliceIndex<[u8]>,

Returns a reference to a byte or sub-byteslice, without doing bounds checking.

For a safe alternative see get.

Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used.

Examples
use spinoso_string::String;

let s = String::from("abc");

unsafe {
    assert_eq!(s.get_unchecked(1), &b'b');
}
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pub unsafe fn get_unchecked_mut<I>(&mut self, index: I) -> &mut I::Outputwhere
    I: SliceIndex<[u8]>,

Returns a mutable reference to a byte or sub-byteslice, without doing bounds checking.

For a safe alternative see get_mut.

Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used.

Examples
use spinoso_string::String;

let mut s = String::from("abc");

unsafe {
    let byte = s.get_unchecked_mut(1);
    *byte = b'x';
}
assert_eq!(s, "axc");
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impl String

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pub fn push_byte(&mut self, byte: u8)

Appends a given byte onto the end of this String.

The given byte is not required to be a valid byte given this String’s encoding because encodings are only conventional.

Examples
use spinoso_string::String;

let mut s = String::utf8(b"UTF-8?".to_vec());
s.push_byte(0xFF);
assert_eq!(s, b"UTF-8?\xFF");
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pub fn try_push_codepoint(
    &mut self,
    codepoint: i64
) -> Result<(), InvalidCodepointError>

Try to append a given Unicode codepoint onto the end of this String.

This API is encoding-aware. For UTF-8 strings, the given integer is converted to a char before appending to this String using push_char. For ASCII and binary strings, the given integer is converted to a byte before appending to this String using push_byte.

This function can be used to implement the Ruby method String#<< for Integer arguments.

Errors

If this String is conventionally UTF-8 and the given codepoint is not a valid char, an error is returned.

If this String has ASCII or binary encoding and the given codepoint is not a valid byte, an error is returned.

Examples

For UTF-8 strings, the given codepoint is converted to a Unicode scalar value before appending:

use spinoso_string::String;

let mut s = String::utf8(b"".to_vec());
s.try_push_codepoint(b'a' as i64)?;
assert_eq!(s, "a");
assert!(s.try_push_codepoint(0xD83F).is_err());
assert!(s.try_push_codepoint(-1).is_err());

For ASCII and binary strings, the given codepoint must be a valid byte:

use spinoso_string::String;

let mut s = String::binary(b"".to_vec());
s.try_push_codepoint(b'a' as i64)?;
assert_eq!(s, "a");
assert!(s.try_push_codepoint(1024).is_err());
assert!(s.try_push_codepoint(-1).is_err());
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pub fn try_push_int(&mut self, int: i64) -> Result<(), InvalidCodepointError>

A more permissive version of try_push_codepoint which can alter the receiver’s encoding to accommodate the given byte.

Errors

If this String is conventionally UTF-8 and the given codepoint is not a valid char, an error is returned.

If this String has ASCII or binary encoding and the given codepoint is not a valid byte, an error is returned.

Examples

For UTF-8 and binary strings, this function behaves identically to try_push_codepoint.

use spinoso_string::String;

let mut s = String::utf8(b"".to_vec());
s.try_push_int(b'a' as i64)?;
assert_eq!(s, "a");
assert!(s.try_push_int(0xD83F).is_err());
assert!(s.try_push_int(-1).is_err());

let mut s = String::binary(b"".to_vec());
s.try_push_int(b'a' as i64)?;
assert_eq!(s, "a");
assert!(s.try_push_int(1024).is_err());
assert!(s.try_push_int(-1).is_err());

For ASCII strings, the given integer must be a valid byte. If the given integer is outside of the ASCII range, the string’s encoding is changed to Encoding::Binary.

use spinoso_string::{Encoding, String};

let mut s = String::ascii(b"".to_vec());
s.try_push_int(b'a' as i64)?;
assert_eq!(s, "a");
assert_eq!(s.encoding(), Encoding::Ascii);
assert!(s.try_push_int(1024).is_err());
assert!(s.try_push_int(-1).is_err());

s.try_push_int(b'\xFF' as i64)?;
assert_eq!(s, b"a\xFF");
assert_eq!(s.encoding(), Encoding::Binary);
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pub fn push_char(&mut self, ch: char)

Appends a given char onto the end of this String.

The given char is UTF-8 encoded and the UTF-8 bytes are appended to the end of this String.

Examples
use spinoso_string::String;

let mut s = String::from("<3");
s.push_char('💎');
assert_eq!(s, b"<3\xF0\x9F\x92\x8E"); // "<3💎"
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pub fn push_str(&mut self, s: &str)

Appends a given string slice onto the end of this String.

Examples
use spinoso_string::String;

let mut s = String::utf8(b"spinoso".to_vec());
s.push_str("-string");
assert_eq!(s, "spinoso-string");
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pub fn extend_from_slice(&mut self, other: &[u8])

Copies and appends all bytes in a slice to the String.

Iterates over the slice other, copies each element, and then appends it to this String. The other byte slice is traversed in-order.

Examples
use spinoso_string::String;

let mut s = String::from("a");
s.extend_from_slice(&b"bc"[..]);
assert_eq!(s, "abc");
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impl String

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pub fn concat<T: AsRef<[u8]>>(&mut self, other: T)

Appends the given bytes to this String.

See also Extend.

This function can be used to implement the Ruby method String#<< for String arguments.

Examples
use spinoso_string::String;

let mut s = String::ascii(b"abc".to_vec());
s.concat(", easy as 123");
assert_eq!(s, "abc, easy as 123");
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pub fn is_ascii_only(&self) -> bool

Returns true for a string which has only ASCII characters.

ASCII is an encoding that defines 128 codepoints. A byte corresponds to an ASCII codepoint if and only if it is in the inclusive range [0, 127].

This function ignores this String’s encoding.

Examples
use spinoso_string::String;

let s = String::utf8("abc".as_bytes().to_vec());
assert!(s.is_ascii_only());
let s = String::utf8("abc\u{6666}".as_bytes().to_vec());
assert!(!s.is_ascii_only());
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pub fn to_binary(&self) -> Self

Return a newly encoded String with Encoding::Binary encoding.

This function can be used to implement the Ruby method String#b.

Examples
use spinoso_string::{Encoding, String};

let s = String::utf8(b"xyz".to_vec());
assert_eq!(s.encoding(), Encoding::Utf8);
let b = s.to_binary();
assert_eq!(b.encoding(), Encoding::Binary);
assert_eq!(s.as_slice(), b.as_slice());
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pub fn bytesize(&self) -> usize

Returns the length of this String in bytes.

bytesize is an Encoding-oblivious API and is equivalent to String::len.

This function can be used to implement the Ruby method String#bytesize.

Examples
use spinoso_string::String;

let s = String::utf8("💎".as_bytes().to_vec());
assert_eq!(s.bytesize(), 4);
assert_eq!(s.bytesize(), s.len());
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pub fn make_capitalized(&mut self)

Modify this String to have the first character converted to uppercase and the remainder to lowercase.

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pub fn make_lowercase(&mut self)

Modify this String to have all characters converted to lowercase.

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pub fn make_uppercase(&mut self)

Modify this String to have the all characters converted to uppercase.

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pub fn ascii_casecmp(&self, other: &[u8]) -> Ordering

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pub fn unicode_casecmp(&self, other: &String, options: CaseFold) -> Option<bool>

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pub fn center<'a, 'b>(
    &'a self,
    width: usize,
    padding: Option<&'b [u8]>
) -> Result<Center<'a, 'b>, CenterError>

Centers this String in width with the given padding.

This function returns an iterator that yields u8.

If width is greater than the length of this String, the returned iterator yields a byte sequence of length width with the byte content of this String centered and padded with the given padding; otherwise, yields the original bytes.

If the given padding is None, the String is padded with an ASCII space.

Errors

If given an empty padding byte string, this function returns an error. This error is returned regardless of whether the String would be centered with the given

Examples
use spinoso_string::String;
let s = String::from("hello");

assert_eq!(s.center(4, None)?.collect::<Vec<_>>(), b"hello");
assert_eq!(
    s.center(20, None)?.collect::<Vec<_>>(),
    b"       hello        "
);
assert_eq!(
    s.center(20, Some(&b"123"[..]))?.collect::<Vec<_>>(),
    b"1231231hello12312312"
);

This iterator is encoding-aware. Conventionally UTF-8 strings are iterated by UTF-8 byte sequences.

use spinoso_string::String;
let s = String::from("💎");

assert_eq!(s.center(3, None)?.collect::<Vec<_>>(), " 💎 ".as_bytes());
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pub fn chomp<T: AsRef<[u8]>>(&mut self, separator: Option<T>) -> bool

Modifies this String in-place with the given record separator removed from the end of str (if given).

If separator is None (i.e. separator has not been changed from the default Ruby record separator), then chomp also removes carriage return characters (that is it will remove \n, \r, and \r\n). If separator is an empty string, it will remove all trailing newlines from the string.

A None separator does not mean that chomp is passed a nil separator. For str.chomp nil, MRI returns str.dup. For str.chomp! nil, MRI makes no changes to the receiver and returns nil.

This function returns true if self is modified, false otherwise.

Examples
use spinoso_string::String;

let mut s = String::utf8(b"This is a paragraph.\r\n\n\n".to_vec());
let modified = s.chomp(None::<&[u8]>);
assert!(modified);
assert_eq!(s, "This is a paragraph.\r\n\n");

let mut s = String::utf8(b"This is a paragraph.\r\n\n\n".to_vec());
let modified = s.chomp(Some(""));
assert!(modified);
assert_eq!(s, "This is a paragraph.");

let mut s = String::utf8(b"hello\r\n\r\r\n".to_vec());
let modified = s.chomp(None::<&[u8]>);
assert!(modified);
assert_eq!(s, "hello\r\n\r");

let mut s = String::utf8(b"hello\r\n\r\r\n".to_vec());
let modified = s.chomp(Some(""));
assert!(modified);
assert_eq!(s, "hello\r\n\r");

let mut s = String::utf8(b"This is a paragraph.".to_vec());
let modified = s.chomp(Some("."));
assert!(modified);
assert_eq!(s, "This is a paragraph");

let mut s = String::utf8(b"This is a paragraph.".to_vec());
let modified = s.chomp(Some("abc"));
assert!(!modified);
assert_eq!(s, "This is a paragraph.");
source

pub fn chop(&mut self) -> bool

Modifies this String in-place and removes the last character.

This method returns a bool that indicates if this string was modified.

If the string ends with \r\n, both characters are removed. When applying chop to an empty string, the string remains empty.

String::chomp is often a safer alternative, as it leaves the string unchanged if it doesn’t end in a record separator.

Examples
use spinoso_string::String;

let mut s = String::utf8(b"This is a paragraph.\r\n".to_vec());
let modified = s.chop();
assert!(modified);
assert_eq!(s, "This is a paragraph.");

let mut s = String::utf8(b"This is a paragraph.".to_vec());
let modified = s.chop();
assert!(modified);
assert_eq!(s, "This is a paragraph");

let mut s = String::utf8(b"".to_vec());
let modified = s.chop();
assert!(!modified);
assert_eq!(s, "");

let mut s = String::utf8(b"x".to_vec());
let modified = s.chop();
assert!(modified);
assert_eq!(s, "");
source

pub fn chr(&self) -> &[u8]

Returns a one-character string at the beginning of the string.

Examples

Conventionally UTF-8 Strings perform a partial UTF-8 decode to compute the first character.

use spinoso_string::String;

let s = String::utf8(b"abcde".to_vec());
assert_eq!(s.chr(), &b"a"[..]);

let s = String::utf8(b"".to_vec());
assert_eq!(s.chr(), &[]);

let s = String::utf8("🦀spinoso💎".as_bytes().to_vec());
assert_eq!(s.chr(), &b"\xF0\x9F\xA6\x80"[..]);

let s = String::utf8(b"\xFFspinoso".to_vec());
assert_eq!(s.chr(), &b"\xFF"[..]);

For ASCII and binary Strings this function returns a slice of the first byte or the empty slice if the String is empty.

use spinoso_string::String;

let s = String::binary(b"abcde".to_vec());
assert_eq!(s.chr(), &b"a"[..]);

let s = String::binary(b"".to_vec());
assert_eq!(s.chr(), &[]);

let s = String::binary("🦀spinoso💎".as_bytes().to_vec());
assert_eq!(s.chr(), &b"\xF0"[..]);

let s = String::binary(b"\xFFspinoso".to_vec());
assert_eq!(s.chr(), &b"\xFF"[..]);
source

pub fn index<T: AsRef<[u8]>>(
    &self,
    needle: T,
    offset: Option<usize>
) -> Option<usize>

Returns the index of the first occurrence of the given substring in this String.

Returns None if not found. If the second parameter is present, it specifies the position in the string to begin the search.

This function can be used to implement String#index.

Examples
use spinoso_string::String;

let s = String::from("hello");
assert_eq!(s.index("e", None), Some(1));
assert_eq!(s.index("lo", None), Some(3));
assert_eq!(s.index("a", None), None);
assert_eq!(s.index("l", Some(3)), Some(3));
source

pub fn rindex<T: AsRef<[u8]>>(
    &self,
    needle: T,
    offset: Option<usize>
) -> Option<usize>

source

pub fn inspect(&self) -> Inspect<'_>

Returns an iterator that yields a debug representation of the String.

This iterator produces char sequences like "spinoso" and "invalid-\xFF-utf8".

This function can be used to implement the Ruby method String#inspect.

This iterator is encoding-aware. This iterator may yield different chars for the same underlying byte contents depending on the string’s encoding.

source

pub fn ord(&self) -> Result<u32, OrdError>

Returns the Integer ordinal of a one-character string.

Errors

If this String is empty, an error is returned.

If this String is conventionally UTF-8 and the string contents begin with an invalid UTF-8 byte sequence, an error is returned.

source§

impl String

source

pub fn chars(&self) -> Chars<'_>

Returns an iterator over the chars of a String.

This function is encoding-aware. Strings with UTF-8 encoding are only conventionally UTF-8. This iterator yields &[u8] byte slices that correspond to either a valid UTF-8 byte sequence or a single invalid UTF-8 byte. For ASCII encoded and binary encoded strings, this iterator yields slices of single bytes.

For UTF-8 encoded strings, the yielded byte slices can be parsed into chars with str::from_utf8 and str::chars.

Examples

Iterating over the characters of a conventionally UTF-8 string:

use core::str;

use spinoso_string::String;

let s = String::utf8(b"ab\xF0\x9F\x92\x8E\xFF".to_vec());
let mut chars = s.chars();
assert_eq!(chars.next(), Some(&b"a"[..]));
assert_eq!(chars.next().map(str::from_utf8), Some(Ok("b")));
assert_eq!(chars.next(), Some(&[0xF0, 0x9F, 0x92, 0x8E][..]));
assert_eq!(chars.next(), Some(&b"\xFF"[..]));
assert_eq!(chars.next(), None);

Iterating over the characters of a binary string:

use spinoso_string::String;

let s = String::binary("💎".as_bytes().to_vec());
let mut chars = s.chars();
assert_eq!(chars.next(), Some(&[0xF0][..]));
assert_eq!(chars.next(), Some(&[0x9F][..]));
assert_eq!(chars.next(), Some(&[0x92][..]));
assert_eq!(chars.next(), Some(&[0x8E][..]));
assert_eq!(chars.next(), None);
source

pub fn codepoints(&self) -> Result<Codepoints<'_>, CodepointsError>

Returns an iterator over the u32 codepoints of a String.

This function is encoding-aware. Strings with UTF-8 encoding are only conventionally UTF-8. This function only returns Ok for Strings with UTF-8 encoding if the underlying bytes in the String are valid UTF-8. For UTF-8 Strings, this iterator yields the u32 values of the chars in the byte string. For ASCII encoded and binary encoded strings, this iterator yields slices of single bytes.

For UTF-8 encoded strings, the yielded byte slices can be parsed into chars with .into().

Errors

This function requires the String contents to be well-formed with respect to its encoding. This function will return an error if the String has UTF-8 encoding and contains invalid UTF-8 byte sequences.

Examples

Iterating over the codepoints of a conventionally UTF-8 string:

use spinoso_string::{CodepointsError, String};

let s = String::utf8(b"ab\xF0\x9F\x92\x8E\xFF".to_vec());
assert!(matches!(
    s.codepoints(),
    Err(CodepointsError::InvalidUtf8Codepoint)
));

let s = String::utf8("💎".as_bytes().to_vec());
let mut codepoints = s.codepoints()?;
assert_eq!(codepoints.next(), Some(u32::from('💎')));
assert_eq!(codepoints.next(), None);

Iterating over the codepoints of a binary string:

use spinoso_string::String;

let s = String::binary("💎".as_bytes().to_vec());
let mut codepoints = s.codepoints()?;
assert_eq!(codepoints.next(), Some(0xF0));
assert_eq!(codepoints.next(), Some(0x9F));
assert_eq!(codepoints.next(), Some(0x92));
assert_eq!(codepoints.next(), Some(0x8E));
assert_eq!(codepoints.next(), None);
source

pub fn char_len(&self) -> usize

Returns the character length of this String.

This function is encoding-aware. For Strings with UTF-8 encoding, multi-byte Unicode characters are length 1 and invalid UTF-8 bytes are length 1. For Strings with ASCII encoding or binary encoding, this function is equivalent to len and bytesize.

Examples
use spinoso_string::String;

let s = String::utf8(b"abc\xF0\x9F\x92\x8E\xFF".to_vec()); // "abc💎\xFF"
assert_eq!(s.char_len(), 5);

let b = String::binary(b"abc\xF0\x9F\x92\x8E\xFF".to_vec()); // "abc💎\xFF"
assert_eq!(b.char_len(), 8);
source

pub fn get_char(&self, index: usize) -> Option<&[u8]>

Returns the index’th character in the string.

This function is encoding-aware. For Strings with UTF-8 encoding, multi-byte Unicode characters are length 1 and invalid UTF-8 bytes are length 1. For Strings with ASCII encoding or binary encoding, this function is equivalent to get with a range of length 1.

Examples
use spinoso_string::String;

let s = String::utf8(b"abc\xF0\x9F\x92\x8E\xFF".to_vec()); // "abc💎\xFF"
assert_eq!(s.get_char(0), Some(&b"a"[..]));
assert_eq!(s.get_char(1), Some(&b"b"[..]));
assert_eq!(s.get_char(2), Some(&b"c"[..]));
assert_eq!(s.get_char(3), Some("💎".as_bytes()));
assert_eq!(s.get_char(4), Some(&b"\xFF"[..]));
assert_eq!(s.get_char(5), None);

let b = String::binary(b"abc\xF0\x9F\x92\x8E\xFF".to_vec()); // "abc💎\xFF"
assert_eq!(b.get_char(0), Some(&b"a"[..]));
assert_eq!(b.get_char(1), Some(&b"b"[..]));
assert_eq!(b.get_char(2), Some(&b"c"[..]));
assert_eq!(b.get_char(3), Some(&b"\xF0"[..]));
assert_eq!(b.get_char(4), Some(&b"\x9F"[..]));
assert_eq!(b.get_char(5), Some(&b"\x92"[..]));
assert_eq!(b.get_char(6), Some(&b"\x8E"[..]));
assert_eq!(b.get_char(7), Some(&b"\xFF"[..]));
assert_eq!(b.get_char(8), None);
source

pub fn get_char_slice(&self, range: Range<usize>) -> Option<&[u8]>

Returns a substring of characters in the string.

This function is encoding-aware. For Strings with UTF-8 encoding, multi-byte Unicode characters are length 1 and invalid UTF-8 bytes are length 1. For Strings with ASCII encoding or binary encoding, this function is equivalent to get with a range.

Examples
use spinoso_string::String;

let s = String::ascii(b"abc".to_vec());
assert_eq!(s.get_char_slice(1..3), Some("bc".as_bytes()));
assert_eq!(s.get_char_slice(10..15), None);

let s = String::utf8(b"abc\xF0\x9F\x92\x8E\xFF".to_vec()); // "abc💎\xFF"
assert_eq!(s.get_char_slice(1..4), Some("bc💎".as_bytes()));
assert_eq!(s.get_char_slice(4..1), Some("".as_bytes()));
source

pub fn is_valid_encoding(&self) -> bool

Returns true for a String which is encoded correctly.

For this method to return true, Strings with conventionally UTF-8 must be well-formed UTF-8; ASCII-encoded Strings must only contain bytes in the range 0..=127; binary-encoded Strings may contain any byte sequence.

This method is suitable for implementing the Ruby method String#valid_encoding?.

Examples
use spinoso_string::{Encoding, String};

let s = String::utf8(b"xyz".to_vec());
assert!(s.is_valid_encoding());
let s = String::utf8("🚀".to_string().into_bytes());
assert!(s.is_valid_encoding());
let s = String::utf8(b"abc\xFF\xFExyz".to_vec());
assert!(!s.is_valid_encoding());

let s = String::ascii(b"xyz".to_vec());
assert!(s.is_valid_encoding());
let s = String::ascii("🚀".to_string().into_bytes());
assert!(!s.is_valid_encoding());
let s = String::ascii(b"abc\xFF\xFExyz".to_vec());
assert!(!s.is_valid_encoding());

let s = String::binary(b"xyz".to_vec());
assert!(s.is_valid_encoding());
let s = String::binary("🚀".to_string().into_bytes());
assert!(s.is_valid_encoding());
let s = String::binary(b"abc\xFF\xFExyz".to_vec());
assert!(s.is_valid_encoding());
source

pub fn reverse(&mut self)

Reverse the characters in the string.

This function is encoding-aware. For Strings with UTF-8 encoding, multi-byte Unicode characters are reversed treated as one element. For Strings with ASCII encoding or binary encoding, this function is equivalent to reversing the underlying byte slice.

Examples
use spinoso_string::String;

let mut s = String::utf8("再见".as_bytes().to_vec());
s.reverse();
assert_eq!(s, "见再");

Methods from Deref<Target = [u8]>§

1.23.0 · source

pub fn is_ascii(&self) -> bool

Checks if all bytes in this slice are within the ASCII range.

1.23.0 · source

pub fn eq_ignore_ascii_case(&self, other: &[u8]) -> bool

Checks that two slices are an ASCII case-insensitive match.

Same as to_ascii_lowercase(a) == to_ascii_lowercase(b), but without allocating and copying temporaries.

1.23.0 · source

pub fn make_ascii_uppercase(&mut self)

Converts this slice to its ASCII upper case equivalent in-place.

ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’, but non-ASCII letters are unchanged.

To return a new uppercased value without modifying the existing one, use to_ascii_uppercase.

1.23.0 · source

pub fn make_ascii_lowercase(&mut self)

Converts this slice to its ASCII lower case equivalent in-place.

ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’, but non-ASCII letters are unchanged.

To return a new lowercased value without modifying the existing one, use to_ascii_lowercase.

1.60.0 · source

pub fn escape_ascii(&self) -> EscapeAscii<'_>

Returns an iterator that produces an escaped version of this slice, treating it as an ASCII string.

Examples

let s = b"0\t\r\n'\"\\\x9d";
let escaped = s.escape_ascii().to_string();
assert_eq!(escaped, "0\\t\\r\\n\\'\\\"\\\\\\x9d");
source

pub fn trim_ascii_start(&self) -> &[u8]

🔬This is a nightly-only experimental API. (byte_slice_trim_ascii)

Returns a byte slice with leading ASCII whitespace bytes removed.

‘Whitespace’ refers to the definition used by u8::is_ascii_whitespace.

Examples
#![feature(byte_slice_trim_ascii)]

assert_eq!(b" \t hello world\n".trim_ascii_start(), b"hello world\n");
assert_eq!(b"  ".trim_ascii_start(), b"");
assert_eq!(b"".trim_ascii_start(), b"");
source

pub fn trim_ascii_end(&self) -> &[u8]

🔬This is a nightly-only experimental API. (byte_slice_trim_ascii)

Returns a byte slice with trailing ASCII whitespace bytes removed.

‘Whitespace’ refers to the definition used by u8::is_ascii_whitespace.

Examples
#![feature(byte_slice_trim_ascii)]

assert_eq!(b"\r hello world\n ".trim_ascii_end(), b"\r hello world");
assert_eq!(b"  ".trim_ascii_end(), b"");
assert_eq!(b"".trim_ascii_end(), b"");
source

pub fn trim_ascii(&self) -> &[u8]

🔬This is a nightly-only experimental API. (byte_slice_trim_ascii)

Returns a byte slice with leading and trailing ASCII whitespace bytes removed.

‘Whitespace’ refers to the definition used by u8::is_ascii_whitespace.

Examples
#![feature(byte_slice_trim_ascii)]

assert_eq!(b"\r hello world\n ".trim_ascii(), b"hello world");
assert_eq!(b"  ".trim_ascii(), b"");
assert_eq!(b"".trim_ascii(), b"");
source

pub fn sort_floats(&mut self)

🔬This is a nightly-only experimental API. (sort_floats)

Sorts the slice of floats.

This sort is in-place (i.e. does not allocate), O(n * log(n)) worst-case, and uses the ordering defined by f32::total_cmp.

Current implementation

This uses the same sorting algorithm as sort_unstable_by.

Examples
#![feature(sort_floats)]
let mut v = [2.6, -5e-8, f32::NAN, 8.29, f32::INFINITY, -1.0, 0.0, -f32::INFINITY, -0.0];

v.sort_floats();
let sorted = [-f32::INFINITY, -1.0, -5e-8, -0.0, 0.0, 2.6, 8.29, f32::INFINITY, f32::NAN];
assert_eq!(&v[..8], &sorted[..8]);
assert!(v[8].is_nan());
source

pub fn flatten(&self) -> &[T]

🔬This is a nightly-only experimental API. (slice_flatten)

Takes a &[[T; N]], and flattens it to a &[T].

Panics

This panics if the length of the resulting slice would overflow a usize.

This is only possible when flattening a slice of arrays of zero-sized types, and thus tends to be irrelevant in practice. If size_of::<T>() > 0, this will never panic.

Examples
#![feature(slice_flatten)]

assert_eq!([[1, 2, 3], [4, 5, 6]].flatten(), &[1, 2, 3, 4, 5, 6]);

assert_eq!(
    [[1, 2, 3], [4, 5, 6]].flatten(),
    [[1, 2], [3, 4], [5, 6]].flatten(),
);

let slice_of_empty_arrays: &[[i32; 0]] = &[[], [], [], [], []];
assert!(slice_of_empty_arrays.flatten().is_empty());

let empty_slice_of_arrays: &[[u32; 10]] = &[];
assert!(empty_slice_of_arrays.flatten().is_empty());
source

pub fn flatten_mut(&mut self) -> &mut [T]

🔬This is a nightly-only experimental API. (slice_flatten)

Takes a &mut [[T; N]], and flattens it to a &mut [T].

Panics

This panics if the length of the resulting slice would overflow a usize.

This is only possible when flattening a slice of arrays of zero-sized types, and thus tends to be irrelevant in practice. If size_of::<T>() > 0, this will never panic.

Examples
#![feature(slice_flatten)]

fn add_5_to_all(slice: &mut [i32]) {
    for i in slice {
        *i += 5;
    }
}

let mut array = [[1, 2, 3], [4, 5, 6], [7, 8, 9]];
add_5_to_all(array.flatten_mut());
assert_eq!(array, [[6, 7, 8], [9, 10, 11], [12, 13, 14]]);
1.0.0 · source

pub fn len(&self) -> usize

Returns the number of elements in the slice.

Examples
let a = [1, 2, 3];
assert_eq!(a.len(), 3);
1.0.0 · source

pub fn is_empty(&self) -> bool

Returns true if the slice has a length of 0.

Examples
let a = [1, 2, 3];
assert!(!a.is_empty());
1.0.0 · source

pub fn first(&self) -> Option<&T>

Returns the first element of the slice, or None if it is empty.

Examples
let v = [10, 40, 30];
assert_eq!(Some(&10), v.first());

let w: &[i32] = &[];
assert_eq!(None, w.first());
1.0.0 · source

pub fn first_mut(&mut self) -> Option<&mut T>

Returns a mutable pointer to the first element of the slice, or None if it is empty.

Examples
let x = &mut [0, 1, 2];

if let Some(first) = x.first_mut() {
    *first = 5;
}
assert_eq!(x, &[5, 1, 2]);
1.5.0 · source

pub fn split_first(&self) -> Option<(&T, &[T])>

Returns the first and all the rest of the elements of the slice, or None if it is empty.

Examples
let x = &[0, 1, 2];

if let Some((first, elements)) = x.split_first() {
    assert_eq!(first, &0);
    assert_eq!(elements, &[1, 2]);
}
1.5.0 · source

pub fn split_first_mut(&mut self) -> Option<(&mut T, &mut [T])>

Returns the first and all the rest of the elements of the slice, or None if it is empty.

Examples
let x = &mut [0, 1, 2];

if let Some((first, elements)) = x.split_first_mut() {
    *first = 3;
    elements[0] = 4;
    elements[1] = 5;
}
assert_eq!(x, &[3, 4, 5]);
1.5.0 · source

pub fn split_last(&self) -> Option<(&T, &[T])>

Returns the last and all the rest of the elements of the slice, or None if it is empty.

Examples
let x = &[0, 1, 2];

if let Some((last, elements)) = x.split_last() {
    assert_eq!(last, &2);
    assert_eq!(elements, &[0, 1]);
}
1.5.0 · source

pub fn split_last_mut(&mut self) -> Option<(&mut T, &mut [T])>

Returns the last and all the rest of the elements of the slice, or None if it is empty.

Examples
let x = &mut [0, 1, 2];

if let Some((last, elements)) = x.split_last_mut() {
    *last = 3;
    elements[0] = 4;
    elements[1] = 5;
}
assert_eq!(x, &[4, 5, 3]);
1.0.0 · source

pub fn last(&self) -> Option<&T>

Returns the last element of the slice, or None if it is empty.

Examples
let v = [10, 40, 30];
assert_eq!(Some(&30), v.last());

let w: &[i32] = &[];
assert_eq!(None, w.last());
1.0.0 · source

pub fn last_mut(&mut self) -> Option<&mut T>

Returns a mutable pointer to the last item in the slice.

Examples
let x = &mut [0, 1, 2];

if let Some(last) = x.last_mut() {
    *last = 10;
}
assert_eq!(x, &[0, 1, 10]);
1.0.0 · source

pub fn get<I>(&self, index: I) -> Option<&<I as SliceIndex<[T]>>::Output>where
    I: SliceIndex<[T]>,

Returns a reference to an element or subslice depending on the type of index.

  • If given a position, returns a reference to the element at that position or None if out of bounds.
  • If given a range, returns the subslice corresponding to that range, or None if out of bounds.
Examples
let v = [10, 40, 30];
assert_eq!(Some(&40), v.get(1));
assert_eq!(Some(&[10, 40][..]), v.get(0..2));
assert_eq!(None, v.get(3));
assert_eq!(None, v.get(0..4));
1.0.0 · source

pub fn get_mut<I>(
    &mut self,
    index: I
) -> Option<&mut <I as SliceIndex<[T]>>::Output>where
    I: SliceIndex<[T]>,

Returns a mutable reference to an element or subslice depending on the type of index (see get) or None if the index is out of bounds.

Examples
let x = &mut [0, 1, 2];

if let Some(elem) = x.get_mut(1) {
    *elem = 42;
}
assert_eq!(x, &[0, 42, 2]);
1.0.0 · source

pub unsafe fn get_unchecked<I>(
    &self,
    index: I
) -> &<I as SliceIndex<[T]>>::Outputwhere
    I: SliceIndex<[T]>,

Returns a reference to an element or subslice, without doing bounds checking.

For a safe alternative see get.

Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used.

Examples
let x = &[1, 2, 4];

unsafe {
    assert_eq!(x.get_unchecked(1), &2);
}
1.0.0 · source

pub unsafe fn get_unchecked_mut<I>(
    &mut self,
    index: I
) -> &mut <I as SliceIndex<[T]>>::Outputwhere
    I: SliceIndex<[T]>,

Returns a mutable reference to an element or subslice, without doing bounds checking.

For a safe alternative see get_mut.

Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used.

Examples
let x = &mut [1, 2, 4];

unsafe {
    let elem = x.get_unchecked_mut(1);
    *elem = 13;
}
assert_eq!(x, &[1, 13, 4]);
1.0.0 · source

pub fn as_ptr(&self) -> *const T

Returns a raw pointer to the slice’s buffer.

The caller must ensure that the slice outlives the pointer this function returns, or else it will end up pointing to garbage.

The caller must also ensure that the memory the pointer (non-transitively) points to is never written to (except inside an UnsafeCell) using this pointer or any pointer derived from it. If you need to mutate the contents of the slice, use as_mut_ptr.

Modifying the container referenced by this slice may cause its buffer to be reallocated, which would also make any pointers to it invalid.

Examples
let x = &[1, 2, 4];
let x_ptr = x.as_ptr();

unsafe {
    for i in 0..x.len() {
        assert_eq!(x.get_unchecked(i), &*x_ptr.add(i));
    }
}
1.0.0 · source

pub fn as_mut_ptr(&mut self) -> *mut T

Returns an unsafe mutable pointer to the slice’s buffer.

The caller must ensure that the slice outlives the pointer this function returns, or else it will end up pointing to garbage.

Modifying the container referenced by this slice may cause its buffer to be reallocated, which would also make any pointers to it invalid.

Examples
let x = &mut [1, 2, 4];
let x_ptr = x.as_mut_ptr();

unsafe {
    for i in 0..x.len() {
        *x_ptr.add(i) += 2;
    }
}
assert_eq!(x, &[3, 4, 6]);
1.48.0 · source

pub fn as_ptr_range(&self) -> Range<*const T>

Returns the two raw pointers spanning the slice.

The returned range is half-open, which means that the end pointer points one past the last element of the slice. This way, an empty slice is represented by two equal pointers, and the difference between the two pointers represents the size of the slice.

See as_ptr for warnings on using these pointers. The end pointer requires extra caution, as it does not point to a valid element in the slice.

This function is useful for interacting with foreign interfaces which use two pointers to refer to a range of elements in memory, as is common in C++.

It can also be useful to check if a pointer to an element refers to an element of this slice:

let a = [1, 2, 3];
let x = &a[1] as *const _;
let y = &5 as *const _;

assert!(a.as_ptr_range().contains(&x));
assert!(!a.as_ptr_range().contains(&y));
1.48.0 · source

pub fn as_mut_ptr_range(&mut self) -> Range<*mut T>

Returns the two unsafe mutable pointers spanning the slice.

The returned range is half-open, which means that the end pointer points one past the last element of the slice. This way, an empty slice is represented by two equal pointers, and the difference between the two pointers represents the size of the slice.

See as_mut_ptr for warnings on using these pointers. The end pointer requires extra caution, as it does not point to a valid element in the slice.

This function is useful for interacting with foreign interfaces which use two pointers to refer to a range of elements in memory, as is common in C++.

1.0.0 · source

pub fn swap(&mut self, a: usize, b: usize)

Swaps two elements in the slice.

Arguments
  • a - The index of the first element
  • b - The index of the second element
Panics

Panics if a or b are out of bounds.

Examples
let mut v = ["a", "b", "c", "d", "e"];
v.swap(2, 4);
assert!(v == ["a", "b", "e", "d", "c"]);
source

pub unsafe fn swap_unchecked(&mut self, a: usize, b: usize)

🔬This is a nightly-only experimental API. (slice_swap_unchecked)

Swaps two elements in the slice, without doing bounds checking.

For a safe alternative see swap.

Arguments
  • a - The index of the first element
  • b - The index of the second element
Safety

Calling this method with an out-of-bounds index is undefined behavior. The caller has to ensure that a < self.len() and b < self.len().

Examples
#![feature(slice_swap_unchecked)]

let mut v = ["a", "b", "c", "d"];
// SAFETY: we know that 1 and 3 are both indices of the slice
unsafe { v.swap_unchecked(1, 3) };
assert!(v == ["a", "d", "c", "b"]);
1.0.0 · source

pub fn reverse(&mut self)

Reverses the order of elements in the slice, in place.

Examples
let mut v = [1, 2, 3];
v.reverse();
assert!(v == [3, 2, 1]);
1.0.0 · source

pub fn iter(&self) -> Iter<'_, T>

Returns an iterator over the slice.

The iterator yields all items from start to end.

Examples
let x = &[1, 2, 4];
let mut iterator = x.iter();

assert_eq!(iterator.next(), Some(&1));
assert_eq!(iterator.next(), Some(&2));
assert_eq!(iterator.next(), Some(&4));
assert_eq!(iterator.next(), None);
1.0.0 · source

pub fn iter_mut(&mut self) -> IterMut<'_, T>

Returns an iterator that allows modifying each value.

The iterator yields all items from start to end.

Examples
let x = &mut [1, 2, 4];
for elem in x.iter_mut() {
    *elem += 2;
}
assert_eq!(x, &[3, 4, 6]);
1.0.0 · source

pub fn windows(&self, size: usize) -> Windows<'_, T>

Returns an iterator over all contiguous windows of length size. The windows overlap. If the slice is shorter than size, the iterator returns no values.

Panics

Panics if size is 0.

Examples
let slice = ['r', 'u', 's', 't'];
let mut iter = slice.windows(2);
assert_eq!(iter.next().unwrap(), &['r', 'u']);
assert_eq!(iter.next().unwrap(), &['u', 's']);
assert_eq!(iter.next().unwrap(), &['s', 't']);
assert!(iter.next().is_none());

If the slice is shorter than size:

let slice = ['f', 'o', 'o'];
let mut iter = slice.windows(4);
assert!(iter.next().is_none());

There’s no windows_mut, as that existing would let safe code violate the “only one &mut at a time to the same thing” rule. However, you can sometimes use Cell::as_slice_of_cells in conjunction with windows to accomplish something similar:

use std::cell::Cell;

let mut array = ['R', 'u', 's', 't', ' ', '2', '0', '1', '5'];
let slice = &mut array[..];
let slice_of_cells: &[Cell<char>] = Cell::from_mut(slice).as_slice_of_cells();
for w in slice_of_cells.windows(3) {
    Cell::swap(&w[0], &w[2]);
}
assert_eq!(array, ['s', 't', ' ', '2', '0', '1', '5', 'u', 'R']);
1.0.0 · source

pub fn chunks(&self, chunk_size: usize) -> Chunks<'_, T>

Returns an iterator over chunk_size elements of the slice at a time, starting at the beginning of the slice.

The chunks are slices and do not overlap. If chunk_size does not divide the length of the slice, then the last chunk will not have length chunk_size.

See chunks_exact for a variant of this iterator that returns chunks of always exactly chunk_size elements, and rchunks for the same iterator but starting at the end of the slice.

Panics

Panics if chunk_size is 0.

Examples
let slice = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.chunks(2);
assert_eq!(iter.next().unwrap(), &['l', 'o']);
assert_eq!(iter.next().unwrap(), &['r', 'e']);
assert_eq!(iter.next().unwrap(), &['m']);
assert!(iter.next().is_none());
1.0.0 · source

pub fn chunks_mut(&mut self, chunk_size: usize) -> ChunksMut<'_, T>

Returns an iterator over chunk_size elements of the slice at a time, starting at the beginning of the slice.

The chunks are mutable slices, and do not overlap. If chunk_size does not divide the length of the slice, then the last chunk will not have length chunk_size.

See chunks_exact_mut for a variant of this iterator that returns chunks of always exactly chunk_size elements, and rchunks_mut for the same iterator but starting at the end of the slice.

Panics

Panics if chunk_size is 0.

Examples
let v = &mut [0, 0, 0, 0, 0];
let mut count = 1;

for chunk in v.chunks_mut(2) {
    for elem in chunk.iter_mut() {
        *elem += count;
    }
    count += 1;
}
assert_eq!(v, &[1, 1, 2, 2, 3]);
1.31.0 · source

pub fn chunks_exact(&self, chunk_size: usize) -> ChunksExact<'_, T>

Returns an iterator over chunk_size elements of the slice at a time, starting at the beginning of the slice.

The chunks are slices and do not overlap. If chunk_size does not divide the length of the slice, then the last up to chunk_size-1 elements will be omitted and can be retrieved from the remainder function of the iterator.

Due to each chunk having exactly chunk_size elements, the compiler can often optimize the resulting code better than in the case of chunks.

See chunks for a variant of this iterator that also returns the remainder as a smaller chunk, and rchunks_exact for the same iterator but starting at the end of the slice.

Panics

Panics if chunk_size is 0.

Examples
let slice = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.chunks_exact(2);
assert_eq!(iter.next().unwrap(), &['l', 'o']);
assert_eq!(iter.next().unwrap(), &['r', 'e']);
assert!(iter.next().is_none());
assert_eq!(iter.remainder(), &['m']);
1.31.0 · source

pub fn chunks_exact_mut(&mut self, chunk_size: usize) -> ChunksExactMut<'_, T>

Returns an iterator over chunk_size elements of the slice at a time, starting at the beginning of the slice.

The chunks are mutable slices, and do not overlap. If chunk_size does not divide the length of the slice, then the last up to chunk_size-1 elements will be omitted and can be retrieved from the into_remainder function of the iterator.

Due to each chunk having exactly chunk_size elements, the compiler can often optimize the resulting code better than in the case of chunks_mut.

See chunks_mut for a variant of this iterator that also returns the remainder as a smaller chunk, and rchunks_exact_mut for the same iterator but starting at the end of the slice.

Panics

Panics if chunk_size is 0.

Examples
let v = &mut [0, 0, 0, 0, 0];
let mut count = 1;

for chunk in v.chunks_exact_mut(2) {
    for elem in chunk.iter_mut() {
        *elem += count;
    }
    count += 1;
}
assert_eq!(v, &[1, 1, 2, 2, 0]);
source

pub unsafe fn as_chunks_unchecked<const N: usize>(&self) -> &[[T; N]]

🔬This is a nightly-only experimental API. (slice_as_chunks)

Splits the slice into a slice of N-element arrays, assuming that there’s no remainder.

Safety

This may only be called when

  • The slice splits exactly into N-element chunks (aka self.len() % N == 0).
  • N != 0.
Examples
#![feature(slice_as_chunks)]
let slice: &[char] = &['l', 'o', 'r', 'e', 'm', '!'];
let chunks: &[[char; 1]] =
    // SAFETY: 1-element chunks never have remainder
    unsafe { slice.as_chunks_unchecked() };
assert_eq!(chunks, &[['l'], ['o'], ['r'], ['e'], ['m'], ['!']]);
let chunks: &[[char; 3]] =
    // SAFETY: The slice length (6) is a multiple of 3
    unsafe { slice.as_chunks_unchecked() };
assert_eq!(chunks, &[['l', 'o', 'r'], ['e', 'm', '!']]);

// These would be unsound:
// let chunks: &[[_; 5]] = slice.as_chunks_unchecked() // The slice length is not a multiple of 5
// let chunks: &[[_; 0]] = slice.as_chunks_unchecked() // Zero-length chunks are never allowed
source

pub fn as_chunks<const N: usize>(&self) -> (&[[T; N]], &[T])

🔬This is a nightly-only experimental API. (slice_as_chunks)

Splits the slice into a slice of N-element arrays, starting at the beginning of the slice, and a remainder slice with length strictly less than N.

Panics

Panics if N is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

Examples
#![feature(slice_as_chunks)]
let slice = ['l', 'o', 'r', 'e', 'm'];
let (chunks, remainder) = slice.as_chunks();
assert_eq!(chunks, &[['l', 'o'], ['r', 'e']]);
assert_eq!(remainder, &['m']);

If you expect the slice to be an exact multiple, you can combine let-else with an empty slice pattern:

#![feature(slice_as_chunks)]
let slice = ['R', 'u', 's', 't'];
let (chunks, []) = slice.as_chunks::<2>() else {
    panic!("slice didn't have even length")
};
assert_eq!(chunks, &[['R', 'u'], ['s', 't']]);
source

pub fn as_rchunks<const N: usize>(&self) -> (&[T], &[[T; N]])

🔬This is a nightly-only experimental API. (slice_as_chunks)

Splits the slice into a slice of N-element arrays, starting at the end of the slice, and a remainder slice with length strictly less than N.

Panics

Panics if N is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

Examples
#![feature(slice_as_chunks)]
let slice = ['l', 'o', 'r', 'e', 'm'];
let (remainder, chunks) = slice.as_rchunks();
assert_eq!(remainder, &['l']);
assert_eq!(chunks, &[['o', 'r'], ['e', 'm']]);
source

pub fn array_chunks<const N: usize>(&self) -> ArrayChunks<'_, T, N>

🔬This is a nightly-only experimental API. (array_chunks)

Returns an iterator over N elements of the slice at a time, starting at the beginning of the slice.

The chunks are array references and do not overlap. If N does not divide the length of the slice, then the last up to N-1 elements will be omitted and can be retrieved from the remainder function of the iterator.

This method is the const generic equivalent of chunks_exact.

Panics

Panics if N is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

Examples
#![feature(array_chunks)]
let slice = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.array_chunks();
assert_eq!(iter.next().unwrap(), &['l', 'o']);
assert_eq!(iter.next().unwrap(), &['r', 'e']);
assert!(iter.next().is_none());
assert_eq!(iter.remainder(), &['m']);
source

pub unsafe fn as_chunks_unchecked_mut<const N: usize>(
    &mut self
) -> &mut [[T; N]]

🔬This is a nightly-only experimental API. (slice_as_chunks)

Splits the slice into a slice of N-element arrays, assuming that there’s no remainder.

Safety

This may only be called when

  • The slice splits exactly into N-element chunks (aka self.len() % N == 0).
  • N != 0.
Examples
#![feature(slice_as_chunks)]
let slice: &mut [char] = &mut ['l', 'o', 'r', 'e', 'm', '!'];
let chunks: &mut [[char; 1]] =
    // SAFETY: 1-element chunks never have remainder
    unsafe { slice.as_chunks_unchecked_mut() };
chunks[0] = ['L'];
assert_eq!(chunks, &[['L'], ['o'], ['r'], ['e'], ['m'], ['!']]);
let chunks: &mut [[char; 3]] =
    // SAFETY: The slice length (6) is a multiple of 3
    unsafe { slice.as_chunks_unchecked_mut() };
chunks[1] = ['a', 'x', '?'];
assert_eq!(slice, &['L', 'o', 'r', 'a', 'x', '?']);

// These would be unsound:
// let chunks: &[[_; 5]] = slice.as_chunks_unchecked_mut() // The slice length is not a multiple of 5
// let chunks: &[[_; 0]] = slice.as_chunks_unchecked_mut() // Zero-length chunks are never allowed
source

pub fn as_chunks_mut<const N: usize>(&mut self) -> (&mut [[T; N]], &mut [T])

🔬This is a nightly-only experimental API. (slice_as_chunks)

Splits the slice into a slice of N-element arrays, starting at the beginning of the slice, and a remainder slice with length strictly less than N.

Panics

Panics if N is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

Examples
#![feature(slice_as_chunks)]
let v = &mut [0, 0, 0, 0, 0];
let mut count = 1;

let (chunks, remainder) = v.as_chunks_mut();
remainder[0] = 9;
for chunk in chunks {
    *chunk = [count; 2];
    count += 1;
}
assert_eq!(v, &[1, 1, 2, 2, 9]);
source

pub fn as_rchunks_mut<const N: usize>(&mut self) -> (&mut [T], &mut [[T; N]])

🔬This is a nightly-only experimental API. (slice_as_chunks)

Splits the slice into a slice of N-element arrays, starting at the end of the slice, and a remainder slice with length strictly less than N.

Panics

Panics if N is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

Examples
#![feature(slice_as_chunks)]
let v = &mut [0, 0, 0, 0, 0];
let mut count = 1;

let (remainder, chunks) = v.as_rchunks_mut();
remainder[0] = 9;
for chunk in chunks {
    *chunk = [count; 2];
    count += 1;
}
assert_eq!(v, &[9, 1, 1, 2, 2]);
source

pub fn array_chunks_mut<const N: usize>(&mut self) -> ArrayChunksMut<'_, T, N>

🔬This is a nightly-only experimental API. (array_chunks)

Returns an iterator over N elements of the slice at a time, starting at the beginning of the slice.

The chunks are mutable array references and do not overlap. If N does not divide the length of the slice, then the last up to N-1 elements will be omitted and can be retrieved from the into_remainder function of the iterator.

This method is the const generic equivalent of chunks_exact_mut.

Panics

Panics if N is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

Examples
#![feature(array_chunks)]
let v = &mut [0, 0, 0, 0, 0];
let mut count = 1;

for chunk in v.array_chunks_mut() {
    *chunk = [count; 2];
    count += 1;
}
assert_eq!(v, &[1, 1, 2, 2, 0]);
source

pub fn array_windows<const N: usize>(&self) -> ArrayWindows<'_, T, N>

🔬This is a nightly-only experimental API. (array_windows)

Returns an iterator over overlapping windows of N elements of a slice, starting at the beginning of the slice.

This is the const generic equivalent of windows.

If N is greater than the size of the slice, it will return no windows.

Panics

Panics if N is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

Examples
#![feature(array_windows)]
let slice = [0, 1, 2, 3];
let mut iter = slice.array_windows();
assert_eq!(iter.next().unwrap(), &[0, 1]);
assert_eq!(iter.next().unwrap(), &[1, 2]);
assert_eq!(iter.next().unwrap(), &[2, 3]);
assert!(iter.next().is_none());
1.31.0 · source

pub fn rchunks(&self, chunk_size: usize) -> RChunks<'_, T>

Returns an iterator over chunk_size elements of the slice at a time, starting at the end of the slice.

The chunks are slices and do not overlap. If chunk_size does not divide the length of the slice, then the last chunk will not have length chunk_size.

See rchunks_exact for a variant of this iterator that returns chunks of always exactly chunk_size elements, and chunks for the same iterator but starting at the beginning of the slice.

Panics

Panics if chunk_size is 0.

Examples
let slice = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.rchunks(2);
assert_eq!(iter.next().unwrap(), &['e', 'm']);
assert_eq!(iter.next().unwrap(), &['o', 'r']);
assert_eq!(iter.next().unwrap(), &['l']);
assert!(iter.next().is_none());
1.31.0 · source

pub fn rchunks_mut(&mut self, chunk_size: usize) -> RChunksMut<'_, T>

Returns an iterator over chunk_size elements of the slice at a time, starting at the end of the slice.

The chunks are mutable slices, and do not overlap. If chunk_size does not divide the length of the slice, then the last chunk will not have length chunk_size.

See rchunks_exact_mut for a variant of this iterator that returns chunks of always exactly chunk_size elements, and chunks_mut for the same iterator but starting at the beginning of the slice.

Panics

Panics if chunk_size is 0.

Examples
let v = &mut [0, 0, 0, 0, 0];
let mut count = 1;

for chunk in v.rchunks_mut(2) {
    for elem in chunk.iter_mut() {
        *elem += count;
    }
    count += 1;
}
assert_eq!(v, &[3, 2, 2, 1, 1]);
1.31.0 · source

pub fn rchunks_exact(&self, chunk_size: usize) -> RChunksExact<'_, T>

Returns an iterator over chunk_size elements of the slice at a time, starting at the end of the slice.

The chunks are slices and do not overlap. If chunk_size does not divide the length of the slice, then the last up to chunk_size-1 elements will be omitted and can be retrieved from the remainder function of the iterator.

Due to each chunk having exactly chunk_size elements, the compiler can often optimize the resulting code better than in the case of rchunks.

See rchunks for a variant of this iterator that also returns the remainder as a smaller chunk, and chunks_exact for the same iterator but starting at the beginning of the slice.

Panics

Panics if chunk_size is 0.

Examples
let slice = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.rchunks_exact(2);
assert_eq!(iter.next().unwrap(), &['e', 'm']);
assert_eq!(iter.next().unwrap(), &['o', 'r']);
assert!(iter.next().is_none());
assert_eq!(iter.remainder(), &['l']);
1.31.0 · source

pub fn rchunks_exact_mut(&mut self, chunk_size: usize) -> RChunksExactMut<'_, T>

Returns an iterator over chunk_size elements of the slice at a time, starting at the end of the slice.

The chunks are mutable slices, and do not overlap. If chunk_size does not divide the length of the slice, then the last up to chunk_size-1 elements will be omitted and can be retrieved from the into_remainder function of the iterator.

Due to each chunk having exactly chunk_size elements, the compiler can often optimize the resulting code better than in the case of chunks_mut.

See rchunks_mut for a variant of this iterator that also returns the remainder as a smaller chunk, and chunks_exact_mut for the same iterator but starting at the beginning of the slice.

Panics

Panics if chunk_size is 0.

Examples
let v = &mut [0, 0, 0, 0, 0];
let mut count = 1;

for chunk in v.rchunks_exact_mut(2) {
    for elem in chunk.iter_mut() {
        *elem += count;
    }
    count += 1;
}
assert_eq!(v, &[0, 2, 2, 1, 1]);
source

pub fn group_by<F>(&self, pred: F) -> GroupBy<'_, T, F>where
    F: FnMut(&T, &T) -> bool,

🔬This is a nightly-only experimental API. (slice_group_by)

Returns an iterator over the slice producing non-overlapping runs of elements using the predicate to separate them.

The predicate is called on two elements following themselves, it means the predicate is called on slice[0] and slice[1] then on slice[1] and slice[2] and so on.

Examples
#![feature(slice_group_by)]

let slice = &[1, 1, 1, 3, 3, 2, 2, 2];

let mut iter = slice.group_by(|a, b| a == b);

assert_eq!(iter.next(), Some(&[1, 1, 1][..]));
assert_eq!(iter.next(), Some(&[3, 3][..]));
assert_eq!(iter.next(), Some(&[2, 2, 2][..]));
assert_eq!(iter.next(), None);

This method can be used to extract the sorted subslices:

#![feature(slice_group_by)]

let slice = &[1, 1, 2, 3, 2, 3, 2, 3, 4];

let mut iter = slice.group_by(|a, b| a <= b);

assert_eq!(iter.next(), Some(&[1, 1, 2, 3][..]));
assert_eq!(iter.next(), Some(&[2, 3][..]));
assert_eq!(iter.next(), Some(&[2, 3, 4][..]));
assert_eq!(iter.next(), None);
source

pub fn group_by_mut<F>(&mut self, pred: F) -> GroupByMut<'_, T, F>where
    F: FnMut(&T, &T) -> bool,

🔬This is a nightly-only experimental API. (slice_group_by)

Returns an iterator over the slice producing non-overlapping mutable runs of elements using the predicate to separate them.

The predicate is called on two elements following themselves, it means the predicate is called on slice[0] and slice[1] then on slice[1] and slice[2] and so on.

Examples
#![feature(slice_group_by)]

let slice = &mut [1, 1, 1, 3, 3, 2, 2, 2];

let mut iter = slice.group_by_mut(|a, b| a == b);

assert_eq!(iter.next(), Some(&mut [1, 1, 1][..]));
assert_eq!(iter.next(), Some(&mut [3, 3][..]));
assert_eq!(iter.next(), Some(&mut [2, 2, 2][..]));
assert_eq!(iter.next(), None);

This method can be used to extract the sorted subslices:

#![feature(slice_group_by)]

let slice = &mut [1, 1, 2, 3, 2, 3, 2, 3, 4];

let mut iter = slice.group_by_mut(|a, b| a <= b);

assert_eq!(iter.next(), Some(&mut [1, 1, 2, 3][..]));
assert_eq!(iter.next(), Some(&mut [2, 3][..]));
assert_eq!(iter.next(), Some(&mut [2, 3, 4][..]));
assert_eq!(iter.next(), None);
1.0.0 · source

pub fn split_at(&self, mid: usize) -> (&[T], &[T])

Divides one slice into two at an index.

The first will contain all indices from [0, mid) (excluding the index mid itself) and the second will contain all indices from [mid, len) (excluding the index len itself).

Panics

Panics if mid > len.

Examples
let v = [1, 2, 3, 4, 5, 6];

{
   let (left, right) = v.split_at(0);
   assert_eq!(left, []);
   assert_eq!(right, [1, 2, 3, 4, 5, 6]);
}

{
    let (left, right) = v.split_at(2);
    assert_eq!(left, [1, 2]);
    assert_eq!(right, [3, 4, 5, 6]);
}

{
    let (left, right) = v.split_at(6);
    assert_eq!(left, [1, 2, 3, 4, 5, 6]);
    assert_eq!(right, []);
}
1.0.0 · source

pub fn split_at_mut(&mut self, mid: usize) -> (&mut [T], &mut [T])

Divides one mutable slice into two at an index.

The first will contain all indices from [0, mid) (excluding the index mid itself) and the second will contain all indices from [mid, len) (excluding the index len itself).

Panics

Panics if mid > len.

Examples
let mut v = [1, 0, 3, 0, 5, 6];
let (left, right) = v.split_at_mut(2);
assert_eq!(left, [1, 0]);
assert_eq!(right, [3, 0, 5, 6]);
left[1] = 2;
right[1] = 4;
assert_eq!(v, [1, 2, 3, 4, 5, 6]);
source

pub unsafe fn split_at_unchecked(&self, mid: usize) -> (&[T], &[T])

🔬This is a nightly-only experimental API. (slice_split_at_unchecked)

Divides one slice into two at an index, without doing bounds checking.

The first will contain all indices from [0, mid) (excluding the index mid itself) and the second will contain all indices from [mid, len) (excluding the index len itself).

For a safe alternative see split_at.

Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used. The caller has to ensure that 0 <= mid <= self.len().

Examples
#![feature(slice_split_at_unchecked)]

let v = [1, 2, 3, 4, 5, 6];

unsafe {
   let (left, right) = v.split_at_unchecked(0);
   assert_eq!(left, []);
   assert_eq!(right, [1, 2, 3, 4, 5, 6]);
}

unsafe {
    let (left, right) = v.split_at_unchecked(2);
    assert_eq!(left, [1, 2]);
    assert_eq!(right, [3, 4, 5, 6]);
}

unsafe {
    let (left, right) = v.split_at_unchecked(6);
    assert_eq!(left, [1, 2, 3, 4, 5, 6]);
    assert_eq!(right, []);
}
source

pub unsafe fn split_at_mut_unchecked(
    &mut self,
    mid: usize
) -> (&mut [T], &mut [T])

🔬This is a nightly-only experimental API. (slice_split_at_unchecked)

Divides one mutable slice into two at an index, without doing bounds checking.

The first will contain all indices from [0, mid) (excluding the index mid itself) and the second will contain all indices from [mid, len) (excluding the index len itself).

For a safe alternative see split_at_mut.

Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used. The caller has to ensure that 0 <= mid <= self.len().

Examples
#![feature(slice_split_at_unchecked)]

let mut v = [1, 0, 3, 0, 5, 6];
// scoped to restrict the lifetime of the borrows
unsafe {
    let (left, right) = v.split_at_mut_unchecked(2);
    assert_eq!(left, [1, 0]);
    assert_eq!(right, [3, 0, 5, 6]);
    left[1] = 2;
    right[1] = 4;
}
assert_eq!(v, [1, 2, 3, 4, 5, 6]);
source

pub fn split_array_ref<const N: usize>(&self) -> (&[T; N], &[T])

🔬This is a nightly-only experimental API. (split_array)

Divides one slice into an array and a remainder slice at an index.

The array will contain all indices from [0, N) (excluding the index N itself) and the slice will contain all indices from [N, len) (excluding the index len itself).

Panics

Panics if N > len.

Examples
#![feature(split_array)]

let v = &[1, 2, 3, 4, 5, 6][..];

{
   let (left, right) = v.split_array_ref::<0>();
   assert_eq!(left, &[]);
   assert_eq!(right, [1, 2, 3, 4, 5, 6]);
}

{
    let (left, right) = v.split_array_ref::<2>();
    assert_eq!(left, &[1, 2]);
    assert_eq!(right, [3, 4, 5, 6]);
}

{
    let (left, right) = v.split_array_ref::<6>();
    assert_eq!(left, &[1, 2, 3, 4, 5, 6]);
    assert_eq!(right, []);
}
source

pub fn split_array_mut<const N: usize>(&mut self) -> (&mut [T; N], &mut [T])

🔬This is a nightly-only experimental API. (split_array)

Divides one mutable slice into an array and a remainder slice at an index.

The array will contain all indices from [0, N) (excluding the index N itself) and the slice will contain all indices from [N, len) (excluding the index len itself).

Panics

Panics if N > len.

Examples
#![feature(split_array)]

let mut v = &mut [1, 0, 3, 0, 5, 6][..];
let (left, right) = v.split_array_mut::<2>();
assert_eq!(left, &mut [1, 0]);
assert_eq!(right, [3, 0, 5, 6]);
left[1] = 2;
right[1] = 4;
assert_eq!(v, [1, 2, 3, 4, 5, 6]);
source

pub fn rsplit_array_ref<const N: usize>(&self) -> (&[T], &[T; N])

🔬This is a nightly-only experimental API. (split_array)

Divides one slice into an array and a remainder slice at an index from the end.

The slice will contain all indices from [0, len - N) (excluding the index len - N itself) and the array will contain all indices from [len - N, len) (excluding the index len itself).

Panics

Panics if N > len.

Examples
#![feature(split_array)]

let v = &[1, 2, 3, 4, 5, 6][..];

{
   let (left, right) = v.rsplit_array_ref::<0>();
   assert_eq!(left, [1, 2, 3, 4, 5, 6]);
   assert_eq!(right, &[]);
}

{
    let (left, right) = v.rsplit_array_ref::<2>();
    assert_eq!(left, [1, 2, 3, 4]);
    assert_eq!(right, &[5, 6]);
}

{
    let (left, right) = v.rsplit_array_ref::<6>();
    assert_eq!(left, []);
    assert_eq!(right, &[1, 2, 3, 4, 5, 6]);
}
source

pub fn rsplit_array_mut<const N: usize>(&mut self) -> (&mut [T], &mut [T; N])

🔬This is a nightly-only experimental API. (split_array)

Divides one mutable slice into an array and a remainder slice at an index from the end.

The slice will contain all indices from [0, len - N) (excluding the index N itself) and the array will contain all indices from [len - N, len) (excluding the index len itself).

Panics

Panics if N > len.

Examples
#![feature(split_array)]

let mut v = &mut [1, 0, 3, 0, 5, 6][..];
let (left, right) = v.rsplit_array_mut::<4>();
assert_eq!(left, [1, 0]);
assert_eq!(right, &mut [3, 0, 5, 6]);
left[1] = 2;
right[1] = 4;
assert_eq!(v, [1, 2, 3, 4, 5, 6]);
1.0.0 · source

pub fn split<F>(&self, pred: F) -> Split<'_, T, F>where
    F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match pred. The matched element is not contained in the subslices.

Examples
let slice = [10, 40, 33, 20];
let mut iter = slice.split(|num| num % 3 == 0);

assert_eq!(iter.next().unwrap(), &[10, 40]);
assert_eq!(iter.next().unwrap(), &[20]);
assert!(iter.next().is_none());

If the first element is matched, an empty slice will be the first item returned by the iterator. Similarly, if the last element in the slice is matched, an empty slice will be the last item returned by the iterator:

let slice = [10, 40, 33];
let mut iter = slice.split(|num| num % 3 == 0);

assert_eq!(iter.next().unwrap(), &[10, 40]);
assert_eq!(iter.next().unwrap(), &[]);
assert!(iter.next().is_none());

If two matched elements are directly adjacent, an empty slice will be present between them:

let slice = [10, 6, 33, 20];
let mut iter = slice.split(|num| num % 3 == 0);

assert_eq!(iter.next().unwrap(), &[10]);
assert_eq!(iter.next().unwrap(), &[]);
assert_eq!(iter.next().unwrap(), &[20]);
assert!(iter.next().is_none());
1.0.0 · source

pub fn split_mut<F>(&mut self, pred: F) -> SplitMut<'_, T, F>where
    F: FnMut(&T) -> bool,

Returns an iterator over mutable subslices separated by elements that match pred. The matched element is not contained in the subslices.

Examples
let mut v = [10, 40, 30, 20, 60, 50];

for group in v.split_mut(|num| *num % 3 == 0) {
    group[0] = 1;
}
assert_eq!(v, [1, 40, 30, 1, 60, 1]);
1.51.0 · source

pub fn split_inclusive<F>(&self, pred: F) -> SplitInclusive<'_, T, F>where
    F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match pred. The matched element is contained in the end of the previous subslice as a terminator.

Examples
let slice = [10, 40, 33, 20];
let mut iter = slice.split_inclusive(|num| num % 3 == 0);

assert_eq!(iter.next().unwrap(), &[10, 40, 33]);
assert_eq!(iter.next().unwrap(), &[20]);
assert!(iter.next().is_none());

If the last element of the slice is matched, that element will be considered the terminator of the preceding slice. That slice will be the last item returned by the iterator.

let slice = [3, 10, 40, 33];
let mut iter = slice.split_inclusive(|num| num % 3 == 0);

assert_eq!(iter.next().unwrap(), &[3]);
assert_eq!(iter.next().unwrap(), &[10, 40, 33]);
assert!(iter.next().is_none());
1.51.0 · source

pub fn split_inclusive_mut<F>(&mut self, pred: F) -> SplitInclusiveMut<'_, T, F>where
    F: FnMut(&T) -> bool,

Returns an iterator over mutable subslices separated by elements that match pred. The matched element is contained in the previous subslice as a terminator.

Examples
let mut v = [10, 40, 30, 20, 60, 50];

for group in v.split_inclusive_mut(|num| *num % 3 == 0) {
    let terminator_idx = group.len()-1;
    group[terminator_idx] = 1;
}
assert_eq!(v, [10, 40, 1, 20, 1, 1]);
1.27.0 · source

pub fn rsplit<F>(&self, pred: F) -> RSplit<'_, T, F>where
    F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match pred, starting at the end of the slice and working backwards. The matched element is not contained in the subslices.

Examples
let slice = [11, 22, 33, 0, 44, 55];
let mut iter = slice.rsplit(|num| *num == 0);

assert_eq!(iter.next().unwrap(), &[44, 55]);
assert_eq!(iter.next().unwrap(), &[11, 22, 33]);
assert_eq!(iter.next(), None);

As with split(), if the first or last element is matched, an empty slice will be the first (or last) item returned by the iterator.

let v = &[0, 1, 1, 2, 3, 5, 8];
let mut it = v.rsplit(|n| *n % 2 == 0);
assert_eq!(it.next().unwrap(), &[]);
assert_eq!(it.next().unwrap(), &[3, 5]);
assert_eq!(it.next().unwrap(), &[1, 1]);
assert_eq!(it.next().unwrap(), &[]);
assert_eq!(it.next(), None);
1.27.0 · source

pub fn rsplit_mut<F>(&mut self, pred: F) -> RSplitMut<'_, T, F>where
    F: FnMut(&T) -> bool,

Returns an iterator over mutable subslices separated by elements that match pred, starting at the end of the slice and working backwards. The matched element is not contained in the subslices.

Examples
let mut v = [100, 400, 300, 200, 600, 500];

let mut count = 0;
for group in v.rsplit_mut(|num| *num % 3 == 0) {
    count += 1;
    group[0] = count;
}
assert_eq!(v, [3, 400, 300, 2, 600, 1]);
1.0.0 · source

pub fn splitn<F>(&self, n: usize, pred: F) -> SplitN<'_, T, F>where
    F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match pred, limited to returning at most n items. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

Examples

Print the slice split once by numbers divisible by 3 (i.e., [10, 40], [20, 60, 50]):

let v = [10, 40, 30, 20, 60, 50];

for group in v.splitn(2, |num| *num % 3 == 0) {
    println!("{group:?}");
}
1.0.0 · source

pub fn splitn_mut<F>(&mut self, n: usize, pred: F) -> SplitNMut<'_, T, F>where
    F: FnMut(&T) -> bool,

Returns an iterator over mutable subslices separated by elements that match pred, limited to returning at most n items. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

Examples
let mut v = [10, 40, 30, 20, 60, 50];

for group in v.splitn_mut(2, |num| *num % 3 == 0) {
    group[0] = 1;
}
assert_eq!(v, [1, 40, 30, 1, 60, 50]);
1.0.0 · source

pub fn rsplitn<F>(&self, n: usize, pred: F) -> RSplitN<'_, T, F>where
    F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match pred limited to returning at most n items. This starts at the end of the slice and works backwards. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

Examples

Print the slice split once, starting from the end, by numbers divisible by 3 (i.e., [50], [10, 40, 30, 20]):

let v = [10, 40, 30, 20, 60, 50];

for group in v.rsplitn(2, |num| *num % 3 == 0) {
    println!("{group:?}");
}
1.0.0 · source

pub fn rsplitn_mut<F>(&mut self, n: usize, pred: F) -> RSplitNMut<'_, T, F>where
    F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match pred limited to returning at most n items. This starts at the end of the slice and works backwards. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

Examples
let mut s = [10, 40, 30, 20, 60, 50];

for group in s.rsplitn_mut(2, |num| *num % 3 == 0) {
    group[0] = 1;
}
assert_eq!(s, [1, 40, 30, 20, 60, 1]);
1.0.0 · source

pub fn contains(&self, x: &T) -> boolwhere
    T: PartialEq<T>,

Returns true if the slice contains an element with the given value.

This operation is O(n).

Note that if you have a sorted slice, binary_search may be faster.

Examples
let v = [10, 40, 30];
assert!(v.contains(&30));
assert!(!v.contains(&50));

If you do not have a &T, but some other value that you can compare with one (for example, String implements PartialEq<str>), you can use iter().any:

let v = [String::from("hello"), String::from("world")]; // slice of `String`
assert!(v.iter().any(|e| e == "hello")); // search with `&str`
assert!(!v.iter().any(|e| e == "hi"));
1.0.0 · source

pub fn starts_with(&self, needle: &[T]) -> boolwhere
    T: PartialEq<T>,

Returns true if needle is a prefix of the slice.

Examples
let v = [10, 40, 30];
assert!(v.starts_with(&[10]));
assert!(v.starts_with(&[10, 40]));
assert!(!v.starts_with(&[50]));
assert!(!v.starts_with(&[10, 50]));

Always returns true if needle is an empty slice:

let v = &[10, 40, 30];
assert!(v.starts_with(&[]));
let v: &[u8] = &[];
assert!(v.starts_with(&[]));
1.0.0 · source

pub fn ends_with(&self, needle: &[T]) -> boolwhere
    T: PartialEq<T>,

Returns true if needle is a suffix of the slice.

Examples
let v = [10, 40, 30];
assert!(v.ends_with(&[30]));
assert!(v.ends_with(&[40, 30]));
assert!(!v.ends_with(&[50]));
assert!(!v.ends_with(&[50, 30]));

Always returns true if needle is an empty slice:

let v = &[10, 40, 30];
assert!(v.ends_with(&[]));
let v: &[u8] = &[];
assert!(v.ends_with(&[]));
1.51.0 · source

pub fn strip_prefix<P>(&self, prefix: &P) -> Option<&[T]>where
    P: SlicePattern<Item = T> + ?Sized,
    T: PartialEq<T>,

Returns a subslice with the prefix removed.

If the slice starts with prefix, returns the subslice after the prefix, wrapped in Some. If prefix is empty, simply returns the original slice.

If the slice does not start with prefix, returns None.

Examples
let v = &[10, 40, 30];
assert_eq!(v.strip_prefix(&[10]), Some(&[40, 30][..]));
assert_eq!(v.strip_prefix(&[10, 40]), Some(&[30][..]));
assert_eq!(v.strip_prefix(&[50]), None);
assert_eq!(v.strip_prefix(&[10, 50]), None);

let prefix : &str = "he";
assert_eq!(b"hello".strip_prefix(prefix.as_bytes()),
           Some(b"llo".as_ref()));
1.51.0 · source

pub fn strip_suffix<P>(&self, suffix: &P) -> Option<&[T]>where
    P: SlicePattern<Item = T> + ?Sized,
    T: PartialEq<T>,

Returns a subslice with the suffix removed.

If the slice ends with suffix, returns the subslice before the suffix, wrapped in Some. If suffix is empty, simply returns the original slice.

If the slice does not end with suffix, returns None.

Examples
let v = &[10, 40, 30];
assert_eq!(v.strip_suffix(&[30]), Some(&[10, 40][..]));
assert_eq!(v.strip_suffix(&[40, 30]), Some(&[10][..]));
assert_eq!(v.strip_suffix(&[50]), None);
assert_eq!(v.strip_suffix(&[50, 30]), None);

Binary searches this slice for a given element. This behaves similarly to contains if this slice is sorted.

If the value is found then Result::Ok is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. The index is chosen deterministically, but is subject to change in future versions of Rust. If the value is not found then Result::Err is returned, containing the index where a matching element could be inserted while maintaining sorted order.

See also binary_search_by, binary_search_by_key, and partition_point.

Examples

Looks up a series of four elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in [1, 4].

let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];

assert_eq!(s.binary_search(&13),  Ok(9));
assert_eq!(s.binary_search(&4),   Err(7));
assert_eq!(s.binary_search(&100), Err(13));
let r = s.binary_search(&1);
assert!(match r { Ok(1..=4) => true, _ => false, });

If you want to find that whole range of matching items, rather than an arbitrary matching one, that can be done using partition_point:

let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];

let low = s.partition_point(|x| x < &1);
assert_eq!(low, 1);
let high = s.partition_point(|x| x <= &1);
assert_eq!(high, 5);
let r = s.binary_search(&1);
assert!((low..high).contains(&r.unwrap()));

assert!(s[..low].iter().all(|&x| x < 1));
assert!(s[low..high].iter().all(|&x| x == 1));
assert!(s[high..].iter().all(|&x| x > 1));

// For something not found, the "range" of equal items is empty
assert_eq!(s.partition_point(|x| x < &11), 9);
assert_eq!(s.partition_point(|x| x <= &11), 9);
assert_eq!(s.binary_search(&11), Err(9));

If you want to insert an item to a sorted vector, while maintaining sort order, consider using partition_point:

let mut s = vec![0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
let num = 42;
let idx = s.partition_point(|&x| x < num);
// The above is equivalent to `let idx = s.binary_search(&num).unwrap_or_else(|x| x);`
s.insert(idx, num);
assert_eq!(s, [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 42, 55]);
1.0.0 · source

pub fn binary_search_by<'a, F>(&'a self, f: F) -> Result<usize, usize>where
    F: FnMut(&'a T) -> Ordering,

Binary searches this slice with a comparator function. This behaves similarly to contains if this slice is sorted.

The comparator function should implement an order consistent with the sort order of the underlying slice, returning an order code that indicates whether its argument is Less, Equal or Greater the desired target.

If the value is found then Result::Ok is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. The index is chosen deterministically, but is subject to change in future versions of Rust. If the value is not found then Result::Err is returned, containing the index where a matching element could be inserted while maintaining sorted order.

See also binary_search, binary_search_by_key, and partition_point.

Examples

Looks up a series of four elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in [1, 4].

let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];

let seek = 13;
assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Ok(9));
let seek = 4;
assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(7));
let seek = 100;
assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(13));
let seek = 1;
let r = s.binary_search_by(|probe| probe.cmp(&seek));
assert!(match r { Ok(1..=4) => true, _ => false, });
1.10.0 · source

pub fn binary_search_by_key<'a, B, F>(
    &'a self,
    b: &B,
    f: F
) -> Result<usize, usize>where
    F: FnMut(&'a T) -> B,
    B: Ord,

Binary searches this slice with a key extraction function. This behaves similarly to contains if this slice is sorted.

Assumes that the slice is sorted by the key, for instance with sort_by_key using the same key extraction function.

If the value is found then Result::Ok is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. The index is chosen deterministically, but is subject to change in future versions of Rust. If the value is not found then Result::Err is returned, containing the index where a matching element could be inserted while maintaining sorted order.

See also binary_search, binary_search_by, and partition_point.

Examples

Looks up a series of four elements in a slice of pairs sorted by their second elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in [1, 4].

let s = [(0, 0), (2, 1), (4, 1), (5, 1), (3, 1),
         (1, 2), (2, 3), (4, 5), (5, 8), (3, 13),
         (1, 21), (2, 34), (4, 55)];

assert_eq!(s.binary_search_by_key(&13, |&(a, b)| b),  Ok(9));
assert_eq!(s.binary_search_by_key(&4, |&(a, b)| b),   Err(7));
assert_eq!(s.binary_search_by_key(&100, |&(a, b)| b), Err(13));
let r = s.binary_search_by_key(&1, |&(a, b)| b);
assert!(match r { Ok(1..=4) => true, _ => false, });
1.20.0 · source

pub fn sort_unstable(&mut self)where
    T: Ord,

Sorts the slice, but might not preserve the order of equal elements.

This sort is unstable (i.e., may reorder equal elements), in-place (i.e., does not allocate), and O(n * log(n)) worst-case.

Current implementation

The current algorithm is based on pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

It is typically faster than stable sorting, except in a few special cases, e.g., when the slice consists of several concatenated sorted sequences.

Examples
let mut v = [-5, 4, 1, -3, 2];

v.sort_unstable();
assert!(v == [-5, -3, 1, 2, 4]);
1.20.0 · source

pub fn sort_unstable_by<F>(&mut self, compare: F)where
    F: FnMut(&T, &T) -> Ordering,

Sorts the slice with a comparator function, but might not preserve the order of equal elements.

This sort is unstable (i.e., may reorder equal elements), in-place (i.e., does not allocate), and O(n * log(n)) worst-case.

The comparator function must define a total ordering for the elements in the slice. If the ordering is not total, the order of the elements is unspecified. An order is a total order if it is (for all a, b and c):

  • total and antisymmetric: exactly one of a < b, a == b or a > b is true, and
  • transitive, a < b and b < c implies a < c. The same must hold for both == and >.

For example, while f64 doesn’t implement Ord because NaN != NaN, we can use partial_cmp as our sort function when we know the slice doesn’t contain a NaN.

let mut floats = [5f64, 4.0, 1.0, 3.0, 2.0];
floats.sort_unstable_by(|a, b| a.partial_cmp(b).unwrap());
assert_eq!(floats, [1.0, 2.0, 3.0, 4.0, 5.0]);
Current implementation

The current algorithm is based on pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

It is typically faster than stable sorting, except in a few special cases, e.g., when the slice consists of several concatenated sorted sequences.

Examples
let mut v = [5, 4, 1, 3, 2];
v.sort_unstable_by(|a, b| a.cmp(b));
assert!(v == [1, 2, 3, 4, 5]);

// reverse sorting
v.sort_unstable_by(|a, b| b.cmp(a));
assert!(v == [5, 4, 3, 2, 1]);
1.20.0 · source

pub fn sort_unstable_by_key<K, F>(&mut self, f: F)where
    F: FnMut(&T) -> K,
    K: Ord,

Sorts the slice with a key extraction function, but might not preserve the order of equal elements.

This sort is unstable (i.e., may reorder equal elements), in-place (i.e., does not allocate), and O(m * n * log(n)) worst-case, where the key function is O(m).

Current implementation

The current algorithm is based on pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

Due to its key calling strategy, sort_unstable_by_key is likely to be slower than sort_by_cached_key in cases where the key function is expensive.

Examples
let mut v = [-5i32, 4, 1, -3, 2];

v.sort_unstable_by_key(|k| k.abs());
assert!(v == [1, 2, -3, 4, -5]);
1.49.0 · source

pub fn select_nth_unstable(
    &mut self,
    index: usize
) -> (&mut [T], &mut T, &mut [T])where
    T: Ord,

Reorder the slice such that the element at index is at its final sorted position.

This reordering has the additional property that any value at position i < index will be less than or equal to any value at a position j > index. Additionally, this reordering is unstable (i.e. any number of equal elements may end up at position index), in-place (i.e. does not allocate), and O(n) worst-case. This function is also/ known as “kth element” in other libraries. It returns a triplet of the following from the reordered slice: the subslice prior to index, the element at index, and the subslice after index; accordingly, the values in those two subslices will respectively all be less-than-or-equal-to and greater-than-or-equal-to the value of the element at index.

Current implementation

The current algorithm is based on the quickselect portion of the same quicksort algorithm used for sort_unstable.

Panics

Panics when index >= len(), meaning it always panics on empty slices.

Examples
let mut v = [-5i32, 4, 1, -3, 2];

// Find the median
v.select_nth_unstable(2);

// We are only guaranteed the slice will be one of the following, based on the way we sort
// about the specified index.
assert!(v == [-3, -5, 1, 2, 4] ||
        v == [-5, -3, 1, 2, 4] ||
        v == [-3, -5, 1, 4, 2] ||
        v == [-5, -3, 1, 4, 2]);
1.49.0 · source

pub fn select_nth_unstable_by<F>(
    &mut self,
    index: usize,
    compare: F
) -> (&mut [T], &mut T, &mut [T])where
    F: FnMut(&T, &T) -> Ordering,

Reorder the slice with a comparator function such that the element at index is at its final sorted position.

This reordering has the additional property that any value at position i < index will be less than or equal to any value at a position j > index using the comparator function. Additionally, this reordering is unstable (i.e. any number of equal elements may end up at position index), in-place (i.e. does not allocate), and O(n) worst-case. This function is also known as “kth element” in other libraries. It returns a triplet of the following from the slice reordered according to the provided comparator function: the subslice prior to index, the element at index, and the subslice after index; accordingly, the values in those two subslices will respectively all be less-than-or-equal-to and greater-than-or-equal-to the value of the element at index.

Current implementation

The current algorithm is based on the quickselect portion of the same quicksort algorithm used for sort_unstable.

Panics

Panics when index >= len(), meaning it always panics on empty slices.

Examples
let mut v = [-5i32, 4, 1, -3, 2];

// Find the median as if the slice were sorted in descending order.
v.select_nth_unstable_by(2, |a, b| b.cmp(a));

// We are only guaranteed the slice will be one of the following, based on the way we sort
// about the specified index.
assert!(v == [2, 4, 1, -5, -3] ||
        v == [2, 4, 1, -3, -5] ||
        v == [4, 2, 1, -5, -3] ||
        v == [4, 2, 1, -3, -5]);
1.49.0 · source

pub fn select_nth_unstable_by_key<K, F>(
    &mut self,
    index: usize,
    f: F
) -> (&mut [T], &mut T, &mut [T])where
    F: FnMut(&T) -> K,
    K: Ord,

Reorder the slice with a key extraction function such that the element at index is at its final sorted position.

This reordering has the additional property that any value at position i < index will be less than or equal to any value at a position j > index using the key extraction function. Additionally, this reordering is unstable (i.e. any number of equal elements may end up at position index), in-place (i.e. does not allocate), and O(n) worst-case. This function is also known as “kth element” in other libraries. It returns a triplet of the following from the slice reordered according to the provided key extraction function: the subslice prior to index, the element at index, and the subslice after index; accordingly, the values in those two subslices will respectively all be less-than-or-equal-to and greater-than-or-equal-to the value of the element at index.

Current implementation

The current algorithm is based on the quickselect portion of the same quicksort algorithm used for sort_unstable.

Panics

Panics when index >= len(), meaning it always panics on empty slices.

Examples
let mut v = [-5i32, 4, 1, -3, 2];

// Return the median as if the array were sorted according to absolute value.
v.select_nth_unstable_by_key(2, |a| a.abs());

// We are only guaranteed the slice will be one of the following, based on the way we sort
// about the specified index.
assert!(v == [1, 2, -3, 4, -5] ||
        v == [1, 2, -3, -5, 4] ||
        v == [2, 1, -3, 4, -5] ||
        v == [2, 1, -3, -5, 4]);
source

pub fn partition_dedup(&mut self) -> (&mut [T], &mut [T])where
    T: PartialEq<T>,

🔬This is a nightly-only experimental API. (slice_partition_dedup)

Moves all consecutive repeated elements to the end of the slice according to the PartialEq trait implementation.

Returns two slices. The first contains no consecutive repeated elements. The second contains all the duplicates in no specified order.

If the slice is sorted, the first returned slice contains no duplicates.

Examples
#![feature(slice_partition_dedup)]

let mut slice = [1, 2, 2, 3, 3, 2, 1, 1];

let (dedup, duplicates) = slice.partition_dedup();

assert_eq!(dedup, [1, 2, 3, 2, 1]);
assert_eq!(duplicates, [2, 3, 1]);
source

pub fn partition_dedup_by<F>(&mut self, same_bucket: F) -> (&mut [T], &mut [T])where
    F: FnMut(&mut T, &mut T) -> bool,

🔬This is a nightly-only experimental API. (slice_partition_dedup)

Moves all but the first of consecutive elements to the end of the slice satisfying a given equality relation.

Returns two slices. The first contains no consecutive repeated elements. The second contains all the duplicates in no specified order.

The same_bucket function is passed references to two elements from the slice and must determine if the elements compare equal. The elements are passed in opposite order from their order in the slice, so if same_bucket(a, b) returns true, a is moved at the end of the slice.

If the slice is sorted, the first returned slice contains no duplicates.

Examples
#![feature(slice_partition_dedup)]

let mut slice = ["foo", "Foo", "BAZ", "Bar", "bar", "baz", "BAZ"];

let (dedup, duplicates) = slice.partition_dedup_by(|a, b| a.eq_ignore_ascii_case(b));

assert_eq!(dedup, ["foo", "BAZ", "Bar", "baz"]);
assert_eq!(duplicates, ["bar", "Foo", "BAZ"]);
source

pub fn partition_dedup_by_key<K, F>(&mut self, key: F) -> (&mut [T], &mut [T])where
    F: FnMut(&mut T) -> K,
    K: PartialEq<K>,

🔬This is a nightly-only experimental API. (slice_partition_dedup)

Moves all but the first of consecutive elements to the end of the slice that resolve to the same key.

Returns two slices. The first contains no consecutive repeated elements. The second contains all the duplicates in no specified order.

If the slice is sorted, the first returned slice contains no duplicates.

Examples
#![feature(slice_partition_dedup)]

let mut slice = [10, 20, 21, 30, 30, 20, 11, 13];

let (dedup, duplicates) = slice.partition_dedup_by_key(|i| *i / 10);

assert_eq!(dedup, [10, 20, 30, 20, 11]);
assert_eq!(duplicates, [21, 30, 13]);
1.26.0 · source

pub fn rotate_left(&mut self, mid: usize)

Rotates the slice in-place such that the first mid elements of the slice move to the end while the last self.len() - mid elements move to the front. After calling rotate_left, the element previously at index mid will become the first element in the slice.

Panics

This function will panic if mid is greater than the length of the slice. Note that mid == self.len() does not panic and is a no-op rotation.

Complexity

Takes linear (in self.len()) time.

Examples
let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
a.rotate_left(2);
assert_eq!(a, ['c', 'd', 'e', 'f', 'a', 'b']);

Rotating a subslice:

let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
a[1..5].rotate_left(1);
assert_eq!(a, ['a', 'c', 'd', 'e', 'b', 'f']);
1.26.0 · source

pub fn rotate_right(&mut self, k: usize)

Rotates the slice in-place such that the first self.len() - k elements of the slice move to the end while the last k elements move to the front. After calling rotate_right, the element previously at index self.len() - k will become the first element in the slice.

Panics

This function will panic if k is greater than the length of the slice. Note that k == self.len() does not panic and is a no-op rotation.

Complexity

Takes linear (in self.len()) time.

Examples
let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
a.rotate_right(2);
assert_eq!(a, ['e', 'f', 'a', 'b', 'c', 'd']);

Rotate a subslice:

let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
a[1..5].rotate_right(1);
assert_eq!(a, ['a', 'e', 'b', 'c', 'd', 'f']);
1.50.0 · source

pub fn fill(&mut self, value: T)where
    T: Clone,

Fills self with elements by cloning value.

Examples
let mut buf = vec![0; 10];
buf.fill(1);
assert_eq!(buf, vec![1; 10]);
1.51.0 · source

pub fn fill_with<F>(&mut self, f: F)where
    F: FnMut() -> T,

Fills self with elements returned by calling a closure repeatedly.

This method uses a closure to create new values. If you’d rather Clone a given value, use fill. If you want to use the Default trait to generate values, you can pass Default::default as the argument.

Examples
let mut buf = vec![1; 10];
buf.fill_with(Default::default);
assert_eq!(buf, vec![0; 10]);
1.7.0 · source

pub fn clone_from_slice(&mut self, src: &[T])where
    T: Clone,

Copies the elements from src into self.

The length of src must be the same as self.

Panics

This function will panic if the two slices have different lengths.

Examples

Cloning two elements from a slice into another:

let src = [1, 2, 3, 4];
let mut dst = [0, 0];

// Because the slices have to be the same length,
// we slice the source slice from four elements
// to two. It will panic if we don't do this.
dst.clone_from_slice(&src[2..]);

assert_eq!(src, [1, 2, 3, 4]);
assert_eq!(dst, [3, 4]);

Rust enforces that there can only be one mutable reference with no immutable references to a particular piece of data in a particular scope. Because of this, attempting to use clone_from_slice on a single slice will result in a compile failure:

let mut slice = [1, 2, 3, 4, 5];

slice[..2].clone_from_slice(&slice[3..]); // compile fail!

To work around this, we can use split_at_mut to create two distinct sub-slices from a slice:

let mut slice = [1, 2, 3, 4, 5];

{
    let (left, right) = slice.split_at_mut(2);
    left.clone_from_slice(&right[1..]);
}

assert_eq!(slice, [4, 5, 3, 4, 5]);
1.9.0 · source

pub fn copy_from_slice(&mut self, src: &[T])where
    T: Copy,

Copies all elements from src into self, using a memcpy.

The length of src must be the same as self.

If T does not implement Copy, use clone_from_slice.

Panics

This function will panic if the two slices have different lengths.

Examples

Copying two elements from a slice into another:

let src = [1, 2, 3, 4];
let mut dst = [0, 0];

// Because the slices have to be the same length,
// we slice the source slice from four elements
// to two. It will panic if we don't do this.
dst.copy_from_slice(&src[2..]);

assert_eq!(src, [1, 2, 3, 4]);
assert_eq!(dst, [3, 4]);

Rust enforces that there can only be one mutable reference with no immutable references to a particular piece of data in a particular scope. Because of this, attempting to use copy_from_slice on a single slice will result in a compile failure:

let mut slice = [1, 2, 3, 4, 5];

slice[..2].copy_from_slice(&slice[3..]); // compile fail!

To work around this, we can use split_at_mut to create two distinct sub-slices from a slice:

let mut slice = [1, 2, 3, 4, 5];

{
    let (left, right) = slice.split_at_mut(2);
    left.copy_from_slice(&right[1..]);
}

assert_eq!(slice, [4, 5, 3, 4, 5]);
1.37.0 · source

pub fn copy_within<R>(&mut self, src: R, dest: usize)where
    R: RangeBounds<usize>,
    T: Copy,

Copies elements from one part of the slice to another part of itself, using a memmove.

src is the range within self to copy from. dest is the starting index of the range within self to copy to, which will have the same length as src. The two ranges may overlap. The ends of the two ranges must be less than or equal to self.len().

Panics

This function will panic if either range exceeds the end of the slice, or if the end of src is before the start.

Examples

Copying four bytes within a slice:

let mut bytes = *b"Hello, World!";

bytes.copy_within(1..5, 8);

assert_eq!(&bytes, b"Hello, Wello!");
1.27.0 · source

pub fn swap_with_slice(&mut self, other: &mut [T])

Swaps all elements in self with those in other.

The length of other must be the same as self.

Panics

This function will panic if the two slices have different lengths.

Example

Swapping two elements across slices:

let mut slice1 = [0, 0];
let mut slice2 = [1, 2, 3, 4];

slice1.swap_with_slice(&mut slice2[2..]);

assert_eq!(slice1, [3, 4]);
assert_eq!(slice2, [1, 2, 0, 0]);

Rust enforces that there can only be one mutable reference to a particular piece of data in a particular scope. Because of this, attempting to use swap_with_slice on a single slice will result in a compile failure:

let mut slice = [1, 2, 3, 4, 5];
slice[..2].swap_with_slice(&mut slice[3..]); // compile fail!

To work around this, we can use split_at_mut to create two distinct mutable sub-slices from a slice:

let mut slice = [1, 2, 3, 4, 5];

{
    let (left, right) = slice.split_at_mut(2);
    left.swap_with_slice(&mut right[1..]);
}

assert_eq!(slice, [4, 5, 3, 1, 2]);
1.30.0 · source

pub unsafe fn align_to<U>(&self) -> (&[T], &[U], &[T])

Transmute the slice to a slice of another type, ensuring alignment of the types is maintained.

This method splits the slice into three distinct slices: prefix, correctly aligned middle slice of a new type, and the suffix slice. How exactly the slice is split up is not specified; the middle part may be smaller than necessary. However, if this fails to return a maximal middle part, that is because code is running in a context where performance does not matter, such as a sanitizer attempting to find alignment bugs. Regular code running in a default (debug or release) execution will return a maximal middle part.

This method has no purpose when either input element T or output element U are zero-sized and will return the original slice without splitting anything.

Safety

This method is essentially a transmute with respect to the elements in the returned middle slice, so all the usual caveats pertaining to transmute::<T, U> also apply here.

Examples

Basic usage:

unsafe {
    let bytes: [u8; 7] = [1, 2, 3, 4, 5, 6, 7];
    let (prefix, shorts, suffix) = bytes.align_to::<u16>();
    // less_efficient_algorithm_for_bytes(prefix);
    // more_efficient_algorithm_for_aligned_shorts(shorts);
    // less_efficient_algorithm_for_bytes(suffix);
}
1.30.0 · source

pub unsafe fn align_to_mut<U>(&mut self) -> (&mut [T], &mut [U], &mut [T])

Transmute the mutable slice to a mutable slice of another type, ensuring alignment of the types is maintained.

This method splits the slice into three distinct slices: prefix, correctly aligned middle slice of a new type, and the suffix slice. How exactly the slice is split up is not specified; the middle part may be smaller than necessary. However, if this fails to return a maximal middle part, that is because code is running in a context where performance does not matter, such as a sanitizer attempting to find alignment bugs. Regular code running in a default (debug or release) execution will return a maximal middle part.

This method has no purpose when either input element T or output element U are zero-sized and will return the original slice without splitting anything.

Safety

This method is essentially a transmute with respect to the elements in the returned middle slice, so all the usual caveats pertaining to transmute::<T, U> also apply here.

Examples

Basic usage:

unsafe {
    let mut bytes: [u8; 7] = [1, 2, 3, 4, 5, 6, 7];
    let (prefix, shorts, suffix) = bytes.align_to_mut::<u16>();
    // less_efficient_algorithm_for_bytes(prefix);
    // more_efficient_algorithm_for_aligned_shorts(shorts);
    // less_efficient_algorithm_for_bytes(suffix);
}
source

pub fn as_simd<const LANES: usize>(&self) -> (&[T], &[Simd<T, LANES>], &[T])where
    Simd<T, LANES>: AsRef<[T; LANES]>,
    T: SimdElement,
    LaneCount<LANES>: SupportedLaneCount,

🔬This is a nightly-only experimental API. (portable_simd)

Split a slice into a prefix, a middle of aligned SIMD types, and a suffix.

This is a safe wrapper around slice::align_to, so has the same weak postconditions as that method. You’re only assured that self.len() == prefix.len() + middle.len() * LANES + suffix.len().

Notably, all of the following are possible:

  • prefix.len() >= LANES.
  • middle.is_empty() despite self.len() >= 3 * LANES.
  • suffix.len() >= LANES.

That said, this is a safe method, so if you’re only writing safe code, then this can at most cause incorrect logic, not unsoundness.

Panics

This will panic if the size of the SIMD type is different from LANES times that of the scalar.

At the time of writing, the trait restrictions on Simd<T, LANES> keeps that from ever happening, as only power-of-two numbers of lanes are supported. It’s possible that, in the future, those restrictions might be lifted in a way that would make it possible to see panics from this method for something like LANES == 3.

Examples
#![feature(portable_simd)]
use core::simd::SimdFloat;

let short = &[1, 2, 3];
let (prefix, middle, suffix) = short.as_simd::<4>();
assert_eq!(middle, []); // Not enough elements for anything in the middle

// They might be split in any possible way between prefix and suffix
let it = prefix.iter().chain(suffix).copied();
assert_eq!(it.collect::<Vec<_>>(), vec![1, 2, 3]);

fn basic_simd_sum(x: &[f32]) -> f32 {
    use std::ops::Add;
    use std::simd::f32x4;
    let (prefix, middle, suffix) = x.as_simd();
    let sums = f32x4::from_array([
        prefix.iter().copied().sum(),
        0.0,
        0.0,
        suffix.iter().copied().sum(),
    ]);
    let sums = middle.iter().copied().fold(sums, f32x4::add);
    sums.reduce_sum()
}

let numbers: Vec<f32> = (1..101).map(|x| x as _).collect();
assert_eq!(basic_simd_sum(&numbers[1..99]), 4949.0);
source

pub fn as_simd_mut<const LANES: usize>(
    &mut self
) -> (&mut [T], &mut [Simd<T, LANES>], &mut [T])where
    Simd<T, LANES>: AsMut<[T; LANES]>,
    T: SimdElement,
    LaneCount<LANES>: SupportedLaneCount,

🔬This is a nightly-only experimental API. (portable_simd)

Split a mutable slice into a mutable prefix, a middle of aligned SIMD types, and a mutable suffix.

This is a safe wrapper around slice::align_to_mut, so has the same weak postconditions as that method. You’re only assured that self.len() == prefix.len() + middle.len() * LANES + suffix.len().

Notably, all of the following are possible:

  • prefix.len() >= LANES.
  • middle.is_empty() despite self.len() >= 3 * LANES.
  • suffix.len() >= LANES.

That said, this is a safe method, so if you’re only writing safe code, then this can at most cause incorrect logic, not unsoundness.

This is the mutable version of slice::as_simd; see that for examples.

Panics

This will panic if the size of the SIMD type is different from LANES times that of the scalar.

At the time of writing, the trait restrictions on Simd<T, LANES> keeps that from ever happening, as only power-of-two numbers of lanes are supported. It’s possible that, in the future, those restrictions might be lifted in a way that would make it possible to see panics from this method for something like LANES == 3.

source

pub fn is_sorted(&self) -> boolwhere
    T: PartialOrd<T>,

🔬This is a nightly-only experimental API. (is_sorted)

Checks if the elements of this slice are sorted.

That is, for each element a and its following element b, a <= b must hold. If the slice yields exactly zero or one element, true is returned.

Note that if Self::Item is only PartialOrd, but not Ord, the above definition implies that this function returns false if any two consecutive items are not comparable.

Examples
#![feature(is_sorted)]
let empty: [i32; 0] = [];

assert!([1, 2, 2, 9].is_sorted());
assert!(![1, 3, 2, 4].is_sorted());
assert!([0].is_sorted());
assert!(empty.is_sorted());
assert!(![0.0, 1.0, f32::NAN].is_sorted());
source

pub fn is_sorted_by<'a, F>(&'a self, compare: F) -> boolwhere
    F: FnMut(&'a T, &'a T) -> Option<Ordering>,

🔬This is a nightly-only experimental API. (is_sorted)

Checks if the elements of this slice are sorted using the given comparator function.

Instead of using PartialOrd::partial_cmp, this function uses the given compare function to determine the ordering of two elements. Apart from that, it’s equivalent to is_sorted; see its documentation for more information.

source

pub fn is_sorted_by_key<'a, F, K>(&'a self, f: F) -> boolwhere
    F: FnMut(&'a T) -> K,
    K: PartialOrd<K>,

🔬This is a nightly-only experimental API. (is_sorted)

Checks if the elements of this slice are sorted using the given key extraction function.

Instead of comparing the slice’s elements directly, this function compares the keys of the elements, as determined by f. Apart from that, it’s equivalent to is_sorted; see its documentation for more information.

Examples
#![feature(is_sorted)]

assert!(["c", "bb", "aaa"].is_sorted_by_key(|s| s.len()));
assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));
1.52.0 · source

pub fn partition_point<P>(&self, pred: P) -> usizewhere
    P: FnMut(&T) -> bool,

Returns the index of the partition point according to the given predicate (the index of the first element of the second partition).

The slice is assumed to be partitioned according to the given predicate. This means that all elements for which the predicate returns true are at the start of the slice and all elements for which the predicate returns false are at the end. For example, [7, 15, 3, 5, 4, 12, 6] is partitioned under the predicate x % 2 != 0 (all odd numbers are at the start, all even at the end).

If this slice is not partitioned, the returned result is unspecified and meaningless, as this method performs a kind of binary search.

See also binary_search, binary_search_by, and binary_search_by_key.

Examples
let v = [1, 2, 3, 3, 5, 6, 7];
let i = v.partition_point(|&x| x < 5);

assert_eq!(i, 4);
assert!(v[..i].iter().all(|&x| x < 5));
assert!(v[i..].iter().all(|&x| !(x < 5)));

If all elements of the slice match the predicate, including if the slice is empty, then the length of the slice will be returned:

let a = [2, 4, 8];
assert_eq!(a.partition_point(|x| x < &100), a.len());
let a: [i32; 0] = [];
assert_eq!(a.partition_point(|x| x < &100), 0);

If you want to insert an item to a sorted vector, while maintaining sort order:

let mut s = vec![0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
let num = 42;
let idx = s.partition_point(|&x| x < num);
s.insert(idx, num);
assert_eq!(s, [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 42, 55]);
source

pub fn take<R, 'a>(self: &mut &'a [T], range: R) -> Option<&'a [T]>where
    R: OneSidedRange<usize>,

🔬This is a nightly-only experimental API. (slice_take)

Removes the subslice corresponding to the given range and returns a reference to it.

Returns None and does not modify the slice if the given range is out of bounds.

Note that this method only accepts one-sided ranges such as 2.. or ..6, but not 2..6.

Examples

Taking the first three elements of a slice:

#![feature(slice_take)]

let mut slice: &[_] = &['a', 'b', 'c', 'd'];
let mut first_three = slice.take(..3).unwrap();

assert_eq!(slice, &['d']);
assert_eq!(first_three, &['a', 'b', 'c']);

Taking the last two elements of a slice:

#![feature(slice_take)]

let mut slice: &[_] = &['a', 'b', 'c', 'd'];
let mut tail = slice.take(2..).unwrap();

assert_eq!(slice, &['a', 'b']);
assert_eq!(tail, &['c', 'd']);

Getting None when range is out of bounds:

#![feature(slice_take)]

let mut slice: &[_] = &['a', 'b', 'c', 'd'];

assert_eq!(None, slice.take(5..));
assert_eq!(None, slice.take(..5));
assert_eq!(None, slice.take(..=4));
let expected: &[char] = &['a', 'b', 'c', 'd'];
assert_eq!(Some(expected), slice.take(..4));
source

pub fn take_mut<R, 'a>(self: &mut &'a mut [T], range: R) -> Option<&'a mut [T]>where
    R: OneSidedRange<usize>,

🔬This is a nightly-only experimental API. (slice_take)

Removes the subslice corresponding to the given range and returns a mutable reference to it.

Returns None and does not modify the slice if the given range is out of bounds.

Note that this method only accepts one-sided ranges such as 2.. or ..6, but not 2..6.

Examples

Taking the first three elements of a slice:

#![feature(slice_take)]

let mut slice: &mut [_] = &mut ['a', 'b', 'c', 'd'];
let mut first_three = slice.take_mut(..3).unwrap();

assert_eq!(slice, &mut ['d']);
assert_eq!(first_three, &mut ['a', 'b', 'c']);

Taking the last two elements of a slice:

#![feature(slice_take)]

let mut slice: &mut [_] = &mut ['a', 'b', 'c', 'd'];
let mut tail = slice.take_mut(2..).unwrap();

assert_eq!(slice, &mut ['a', 'b']);
assert_eq!(tail, &mut ['c', 'd']);

Getting None when range is out of bounds:

#![feature(slice_take)]

let mut slice: &mut [_] = &mut ['a', 'b', 'c', 'd'];

assert_eq!(None, slice.take_mut(5..));
assert_eq!(None, slice.take_mut(..5));
assert_eq!(None, slice.take_mut(..=4));
let expected: &mut [_] = &mut ['a', 'b', 'c', 'd'];
assert_eq!(Some(expected), slice.take_mut(..4));
source

pub fn take_first<'a>(self: &mut &'a [T]) -> Option<&'a T>

🔬This is a nightly-only experimental API. (slice_take)

Removes the first element of the slice and returns a reference to it.

Returns None if the slice is empty.

Examples
#![feature(slice_take)]

let mut slice: &[_] = &['a', 'b', 'c'];
let first = slice.take_first().unwrap();

assert_eq!(slice, &['b', 'c']);
assert_eq!(first, &'a');
source

pub fn take_first_mut<'a>(self: &mut &'a mut [T]) -> Option<&'a mut T>

🔬This is a nightly-only experimental API. (slice_take)

Removes the first element of the slice and returns a mutable reference to it.

Returns None if the slice is empty.

Examples
#![feature(slice_take)]

let mut slice: &mut [_] = &mut ['a', 'b', 'c'];
let first = slice.take_first_mut().unwrap();
*first = 'd';

assert_eq!(slice, &['b', 'c']);
assert_eq!(first, &'d');
source

pub fn take_last<'a>(self: &mut &'a [T]) -> Option<&'a T>

🔬This is a nightly-only experimental API. (slice_take)

Removes the last element of the slice and returns a reference to it.

Returns None if the slice is empty.

Examples
#![feature(slice_take)]

let mut slice: &[_] = &['a', 'b', 'c'];
let last = slice.take_last().unwrap();

assert_eq!(slice, &['a', 'b']);
assert_eq!(last, &'c');
source

pub fn take_last_mut<'a>(self: &mut &'a mut [T]) -> Option<&'a mut T>

🔬This is a nightly-only experimental API. (slice_take)

Removes the last element of the slice and returns a mutable reference to it.

Returns None if the slice is empty.

Examples
#![feature(slice_take)]

let mut slice: &mut [_] = &mut ['a', 'b', 'c'];
let last = slice.take_last_mut().unwrap();
*last = 'd';

assert_eq!(slice, &['a', 'b']);
assert_eq!(last, &'d');
source

pub unsafe fn get_many_unchecked_mut<const N: usize>(
    &mut self,
    indices: [usize; N]
) -> [&mut T; N]

🔬This is a nightly-only experimental API. (get_many_mut)

Returns mutable references to many indices at once, without doing any checks.

For a safe alternative see get_many_mut.

Safety

Calling this method with overlapping or out-of-bounds indices is undefined behavior even if the resulting references are not used.

Examples
#![feature(get_many_mut)]

let x = &mut [1, 2, 4];

unsafe {
    let [a, b] = x.get_many_unchecked_mut([0, 2]);
    *a *= 10;
    *b *= 100;
}
assert_eq!(x, &[10, 2, 400]);
source

pub fn get_many_mut<const N: usize>(
    &mut self,
    indices: [usize; N]
) -> Result<[&mut T; N], GetManyMutError<N>>

🔬This is a nightly-only experimental API. (get_many_mut)

Returns mutable references to many indices at once.

Returns an error if any index is out-of-bounds, or if the same index was passed more than once.

Examples
#![feature(get_many_mut)]

let v = &mut [1, 2, 3];
if let Ok([a, b]) = v.get_many_mut([0, 2]) {
    *a = 413;
    *b = 612;
}
assert_eq!(v, &[413, 2, 612]);
source

pub fn sort_floats(&mut self)

🔬This is a nightly-only experimental API. (sort_floats)

Sorts the slice of floats.

This sort is in-place (i.e. does not allocate), O(n * log(n)) worst-case, and uses the ordering defined by f64::total_cmp.

Current implementation

This uses the same sorting algorithm as sort_unstable_by.

Examples
#![feature(sort_floats)]
let mut v = [2.6, -5e-8, f64::NAN, 8.29, f64::INFINITY, -1.0, 0.0, -f64::INFINITY, -0.0];

v.sort_floats();
let sorted = [-f64::INFINITY, -1.0, -5e-8, -0.0, 0.0, 2.6, 8.29, f64::INFINITY, f64::NAN];
assert_eq!(&v[..8], &sorted[..8]);
assert!(v[8].is_nan());
1.0.0 · source

pub fn sort(&mut self)where
    T: Ord,

Sorts the slice.

This sort is stable (i.e., does not reorder equal elements) and O(n * log(n)) worst-case.

When applicable, unstable sorting is preferred because it is generally faster than stable sorting and it doesn’t allocate auxiliary memory. See sort_unstable.

Current implementation

The current algorithm is an adaptive, iterative merge sort inspired by timsort. It is designed to be very fast in cases where the slice is nearly sorted, or consists of two or more sorted sequences concatenated one after another.

Also, it allocates temporary storage half the size of self, but for short slices a non-allocating insertion sort is used instead.

Examples
let mut v = [-5, 4, 1, -3, 2];

v.sort();
assert!(v == [-5, -3, 1, 2, 4]);
1.0.0 · source

pub fn sort_by<F>(&mut self, compare: F)where
    F: FnMut(&T, &T) -> Ordering,

Sorts the slice with a comparator function.

This sort is stable (i.e., does not reorder equal elements) and O(n * log(n)) worst-case.

The comparator function must define a total ordering for the elements in the slice. If the ordering is not total, the order of the elements is unspecified. An order is a total order if it is (for all a, b and c):

  • total and antisymmetric: exactly one of a < b, a == b or a > b is true, and
  • transitive, a < b and b < c implies a < c. The same must hold for both == and >.

For example, while f64 doesn’t implement Ord because NaN != NaN, we can use partial_cmp as our sort function when we know the slice doesn’t contain a NaN.

let mut floats = [5f64, 4.0, 1.0, 3.0, 2.0];
floats.sort_by(|a, b| a.partial_cmp(b).unwrap());
assert_eq!(floats, [1.0, 2.0, 3.0, 4.0, 5.0]);

When applicable, unstable sorting is preferred because it is generally faster than stable sorting and it doesn’t allocate auxiliary memory. See sort_unstable_by.

Current implementation

The current algorithm is an adaptive, iterative merge sort inspired by timsort. It is designed to be very fast in cases where the slice is nearly sorted, or consists of two or more sorted sequences concatenated one after another.

Also, it allocates temporary storage half the size of self, but for short slices a non-allocating insertion sort is used instead.

Examples
let mut v = [5, 4, 1, 3, 2];
v.sort_by(|a, b| a.cmp(b));
assert!(v == [1, 2, 3, 4, 5]);

// reverse sorting
v.sort_by(|a, b| b.cmp(a));
assert!(v == [5, 4, 3, 2, 1]);
1.7.0 · source

pub fn sort_by_key<K, F>(&mut self, f: F)where
    F: FnMut(&T) -> K,
    K: Ord,

Sorts the slice with a key extraction function.

This sort is stable (i.e., does not reorder equal elements) and O(m * n * log(n)) worst-case, where the key function is O(m).

For expensive key functions (e.g. functions that are not simple property accesses or basic operations), sort_by_cached_key is likely to be significantly faster, as it does not recompute element keys.

When applicable, unstable sorting is preferred because it is generally faster than stable sorting and it doesn’t allocate auxiliary memory. See sort_unstable_by_key.

Current implementation

The current algorithm is an adaptive, iterative merge sort inspired by timsort. It is designed to be very fast in cases where the slice is nearly sorted, or consists of two or more sorted sequences concatenated one after another.

Also, it allocates temporary storage half the size of self, but for short slices a non-allocating insertion sort is used instead.

Examples
let mut v = [-5i32, 4, 1, -3, 2];

v.sort_by_key(|k| k.abs());
assert!(v == [1, 2, -3, 4, -5]);
1.34.0 · source

pub fn sort_by_cached_key<K, F>(&mut self, f: F)where
    F: FnMut(&T) -> K,
    K: Ord,

Sorts the slice with a key extraction function.

During sorting, the key function is called at most once per element, by using temporary storage to remember the results of key evaluation. The order of calls to the key function is unspecified and may change in future versions of the standard library.

This sort is stable (i.e., does not reorder equal elements) and O(m * n + n * log(n)) worst-case, where the key function is O(m).

For simple key functions (e.g., functions that are property accesses or basic operations), sort_by_key is likely to be faster.

Current implementation

The current algorithm is based on pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

In the worst case, the algorithm allocates temporary storage in a Vec<(K, usize)> the length of the slice.

Examples
let mut v = [-5i32, 4, 32, -3, 2];

v.sort_by_cached_key(|k| k.to_string());
assert!(v == [-3, -5, 2, 32, 4]);
1.0.0 · source

pub fn to_vec(&self) -> Vec<T, Global> where
    T: Clone,

Copies self into a new Vec.

Examples
let s = [10, 40, 30];
let x = s.to_vec();
// Here, `s` and `x` can be modified independently.
source

pub fn to_vec_in<A>(&self, alloc: A) -> Vec<T, A> where
    A: Allocator,
    T: Clone,

🔬This is a nightly-only experimental API. (allocator_api)

Copies self into a new Vec with an allocator.

Examples
#![feature(allocator_api)]

use std::alloc::System;

let s = [10, 40, 30];
let x = s.to_vec_in(System);
// Here, `s` and `x` can be modified independently.
1.40.0 · source

pub fn repeat(&self, n: usize) -> Vec<T, Global> where
    T: Copy,

Creates a vector by copying a slice n times.

Panics

This function will panic if the capacity would overflow.

Examples

Basic usage:

assert_eq!([1, 2].repeat(3), vec![1, 2, 1, 2, 1, 2]);

A panic upon overflow:

// this will panic at runtime
b"0123456789abcdef".repeat(usize::MAX);
1.0.0 · source

pub fn concat<Item>(&self) -> <[T] as Concat<Item>>::Output where
    [T]: Concat<Item>,
    Item: ?Sized,

Flattens a slice of T into a single value Self::Output.

Examples
assert_eq!(["hello", "world"].concat(), "helloworld");
assert_eq!([[1, 2], [3, 4]].concat(), [1, 2, 3, 4]);
1.3.0 · source

pub fn join<Separator>(&self, sep: Separator) -> <[T] as Join<Separator>>::Output where
    [T]: Join<Separator>,

Flattens a slice of T into a single value Self::Output, placing a given separator between each.

Examples
assert_eq!(["hello", "world"].join(" "), "hello world");
assert_eq!([[1, 2], [3, 4]].join(&0), [1, 2, 0, 3, 4]);
assert_eq!([[1, 2], [3, 4]].join(&[0, 0][..]), [1, 2, 0, 0, 3, 4]);
1.0.0 · source

pub fn connect<Separator>(
    &self,
    sep: Separator
) -> <[T] as Join<Separator>>::Output where
    [T]: Join<Separator>,

👎Deprecated since 1.3.0: renamed to join

Flattens a slice of T into a single value Self::Output, placing a given separator between each.

Examples
assert_eq!(["hello", "world"].connect(" "), "hello world");
assert_eq!([[1, 2], [3, 4]].connect(&0), [1, 2, 0, 3, 4]);
1.23.0 · source

pub fn to_ascii_uppercase(&self) -> Vec<u8, Global>

Returns a vector containing a copy of this slice where each byte is mapped to its ASCII upper case equivalent.

ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’, but non-ASCII letters are unchanged.

To uppercase the value in-place, use make_ascii_uppercase.

1.23.0 · source

pub fn to_ascii_lowercase(&self) -> Vec<u8, Global>

Returns a vector containing a copy of this slice where each byte is mapped to its ASCII lower case equivalent.

ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’, but non-ASCII letters are unchanged.

To lowercase the value in-place, use make_ascii_lowercase.

Trait Implementations§

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impl AsMut<[u8]> for String

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fn as_mut(&mut self) -> &mut [u8]

Converts this type into a mutable reference of the (usually inferred) input type.
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impl AsRef<[u8]> for String

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fn as_ref(&self) -> &[u8]

Converts this type into a shared reference of the (usually inferred) input type.
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impl Borrow<[u8]> for String

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fn borrow(&self) -> &[u8]

Immutably borrows from an owned value. Read more
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impl Clone for String

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fn clone(&self) -> String

Returns a copy of the value. Read more
1.0.0 · source§

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for String

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl Default for String

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fn default() -> String

Returns the “default value” for a type. Read more
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impl Deref for String

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type Target = [u8]

The resulting type after dereferencing.
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fn deref(&self) -> &[u8]

Dereferences the value.
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impl DerefMut for String

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fn deref_mut(&mut self) -> &mut [u8]

Mutably dereferences the value.
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impl<'a> Extend<&'a mut u8> for String

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fn extend<I: IntoIterator<Item = &'a mut u8>>(&mut self, iter: I)

Extends a collection with the contents of an iterator. Read more
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fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)
Extends a collection with exactly one element.
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fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)
Reserves capacity in a collection for the given number of additional elements. Read more
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impl<'a> Extend<&'a u8> for String

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fn extend<I: IntoIterator<Item = &'a u8>>(&mut self, iter: I)

Extends a collection with the contents of an iterator. Read more
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fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)
Extends a collection with exactly one element.
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fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)
Reserves capacity in a collection for the given number of additional elements. Read more
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impl Extend<u8> for String

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fn extend<I: IntoIterator<Item = u8>>(&mut self, iter: I)

Extends a collection with the contents of an iterator. Read more
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fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)
Extends a collection with exactly one element.
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fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)
Reserves capacity in a collection for the given number of additional elements. Read more
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impl<'a> From<&'a [u8]> for String

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fn from(content: &'a [u8]) -> Self

Converts to this type from the input type.
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impl<'a> From<&'a String> for Chars<'a>

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fn from(s: &'a String) -> Self

Converts to this type from the input type.
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impl<'a> From<&'a mut [u8]> for String

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fn from(content: &'a mut [u8]) -> Self

Converts to this type from the input type.
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impl From<&str> for String

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fn from(s: &str) -> Self

Converts to this type from the input type.
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impl<'a> From<Cow<'a, [u8]>> for String

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fn from(content: Cow<'a, [u8]>) -> Self

Converts to this type from the input type.
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impl From<String> for String

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fn from(s: String) -> Self

Converts to this type from the input type.
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impl From<String> for Vec<u8>

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fn from(s: String) -> Self

Converts to this type from the input type.
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impl From<Vec<u8, Global>> for String

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fn from(content: Vec<u8>) -> Self

Converts to this type from the input type.
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impl<'a> FromIterator<&'a char> for String

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fn from_iter<I: IntoIterator<Item = &'a char>>(iter: I) -> Self

Creates a value from an iterator. Read more
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impl<'a> FromIterator<&'a mut char> for String

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fn from_iter<I: IntoIterator<Item = &'a mut char>>(iter: I) -> Self

Creates a value from an iterator. Read more
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impl<'a> FromIterator<&'a mut u8> for String

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fn from_iter<I: IntoIterator<Item = &'a mut u8>>(iter: I) -> Self

Creates a value from an iterator. Read more
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impl<'a> FromIterator<&'a u8> for String

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fn from_iter<I: IntoIterator<Item = &'a u8>>(iter: I) -> Self

Creates a value from an iterator. Read more
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impl FromIterator<char> for String

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fn from_iter<I: IntoIterator<Item = char>>(iter: I) -> Self

Creates a value from an iterator. Read more
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impl FromIterator<u8> for String

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fn from_iter<I: IntoIterator<Item = u8>>(iter: I) -> Self

Creates a value from an iterator. Read more
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impl Hash for String

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fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher. Read more
1.3.0 · source§

fn hash_slice<H>(data: &[Self], state: &mut H)where
    H: Hasher,
    Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl<I: SliceIndex<[u8]>> Index<I> for String

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type Output = <I as SliceIndex<[u8]>>::Output

The returned type after indexing.
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fn index(&self, index: I) -> &Self::Output

Performs the indexing (container[index]) operation. Read more
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impl<I: SliceIndex<[u8]>> IndexMut<I> for String

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fn index_mut(&mut self, index: I) -> &mut Self::Output

Performs the mutable indexing (container[index]) operation. Read more
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impl IntoIterator for String

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fn into_iter(self) -> Self::IntoIter

Returns an iterator that moves over the remaining bytes of a slice

Examples
use spinoso_string::String;

let s = String::from("abc");

let mut iterator = s.into_iter();

assert_eq!(iterator.next(), Some(b'a'));
assert_eq!(iterator.next(), Some(b'b'));
assert_eq!(iterator.next(), Some(b'c'));
assert_eq!(iterator.next(), None);
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type Item = u8

The type of the elements being iterated over.
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type IntoIter = IntoIter

Which kind of iterator are we turning this into?
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impl Ord for String

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fn cmp(&self, other: &String) -> Ordering

This method returns an Ordering between self and other. Read more
1.21.0 · source§

fn max(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the maximum of two values. Read more
1.21.0 · source§

fn min(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the minimum of two values. Read more
1.50.0 · source§

fn clamp(self, min: Self, max: Self) -> Selfwhere
    Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval. Read more
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impl<const N: usize> PartialEq<&[u8; N]> for String

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fn eq(&self, other: &&[u8; N]) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialEq<&[u8]> for String

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fn eq(&self, other: &&[u8]) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialEq<&str> for String

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fn eq(&self, other: &&str) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl<const N: usize> PartialEq<[u8; N]> for String

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fn eq(&self, other: &[u8; N]) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialEq<[u8]> for String

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fn eq(&self, other: &[u8]) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl<const N: usize> PartialEq<String> for &[u8; N]

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fn eq(&self, other: &String) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialEq<String> for &[u8]

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fn eq(&self, other: &String) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialEq<String> for &str

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fn eq(&self, other: &String) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl<const N: usize> PartialEq<String> for [u8; N]

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fn eq(&self, other: &String) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialEq<String> for [u8]

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fn eq(&self, other: &String) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialEq<String> for String

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fn eq(&self, other: &String) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialEq<String> for String

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fn eq(&self, other: &String) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialEq<String> for String

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fn eq(&self, other: &String) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialEq<String> for Vec<u8>

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fn eq(&self, other: &String) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialEq<String> for str

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fn eq(&self, other: &String) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialEq<Vec<u8, Global>> for String

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fn eq(&self, other: &Vec<u8>) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialEq<str> for String

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fn eq(&self, other: &str) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialOrd<String> for String

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fn partial_cmp(&self, other: &String) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
1.0.0 · source§

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
1.0.0 · source§

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
1.0.0 · source§

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
1.0.0 · source§

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl<'a> TryFrom<&'a String> for Codepoints<'a>

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type Error = CodepointsError

The type returned in the event of a conversion error.
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fn try_from(s: &'a String) -> Result<Self, Self::Error>

Performs the conversion.
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impl Write for String

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fn write_fmt(&mut self, args: Arguments<'_>) -> Result

Glue for usage of the write! macro with implementors of this trait. Read more
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fn write_str(&mut self, s: &str) -> Result

Writes a string slice into this writer, returning whether the write succeeded. Read more
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fn write_char(&mut self, c: char) -> Result

Writes a char into this writer, returning whether the write succeeded. Read more
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impl Write for String

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fn write(&mut self, buf: &[u8]) -> Result<usize>

Write a buffer into this writer, returning how many bytes were written. Read more
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fn write_all(&mut self, buf: &[u8]) -> Result<()>

Attempts to write an entire buffer into this writer. Read more
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fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<()>

Writes a formatted string into this writer, returning any error encountered. Read more
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fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize>

Like write, except that it writes from a slice of buffers. Read more
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fn flush(&mut self) -> Result<()>

Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
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fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)
Determines if this Writer has an efficient write_vectored implementation. Read more
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fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)
Attempts to write multiple buffers into this writer. Read more
1.0.0 · source§

fn by_ref(&mut self) -> &mut Selfwhere
    Self: Sized,

Creates a “by reference” adapter for this instance of Write. Read more
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impl Eq for String

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impl StructuralEq for String

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impl StructuralPartialEq for String

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for Twhere
    T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere
    T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere
    T: ?Sized,

const: unstable · source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

const: unstable · source§

fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere
    U: From<T>,

const: unstable · source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for Twhere
    T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for Twhere
    U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
const: unstable · source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere
    U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
const: unstable · source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.