Struct VacantEntry

pub struct VacantEntry<'a, T, S, A: Allocator = Global> { /* private fields */ }

A view into a vacant entry in a HashSet. It is part of the Entry enum.

Examples

use hashbrown::hash_set::{Entry, HashSet, VacantEntry};

let mut set = HashSet::<&str>::new();

let entry_v: VacantEntry<_, _> = match set.entry("a") {
    Entry::Vacant(view) => view,
    Entry::Occupied(_) => unreachable!(),
};
entry_v.insert();
assert!(set.contains("a") && set.len() == 1);

// Nonexistent key (insert)
match set.entry("b") {
    Entry::Vacant(view) => view.insert(),
    Entry::Occupied(_) => unreachable!(),
}
assert!(set.contains("b") && set.len() == 2);

Implementations

impl<'a, T, S, A: Allocator> VacantEntry<'a, T, S, A>

pub fn get(&self) -> &T

Gets a reference to the value that would be used when inserting through the VacantEntry.

Examples

use hashbrown::HashSet;

let mut set: HashSet<&str> = HashSet::new();
assert_eq!(set.entry("poneyland").get(), &"poneyland");

pub fn into_value(self) -> T

Take ownership of the value.

Examples

use hashbrown::hash_set::{Entry, HashSet};

let mut set: HashSet<&str> = HashSet::new();

match set.entry("poneyland") {
    Entry::Occupied(_) => panic!(),
    Entry::Vacant(v) => assert_eq!(v.into_value(), "poneyland"),
}

pub fn insert(self)

where T: Hash, S: BuildHasher,

Sets the value of the entry with the VacantEntry’s value.

Examples

use hashbrown::HashSet;
use hashbrown::hash_set::Entry;

let mut set: HashSet<&str> = HashSet::new();

if let Entry::Vacant(o) = set.entry("poneyland") {
    o.insert();
}
assert!(set.contains("poneyland"));

Trait Implementations

impl<T: Debug, S, A: Allocator> Debug for VacantEntry<'_, T, S, A>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.