Struct VacantEntry

pub struct VacantEntry<'a, K: 'a, V: 'a, A: Allocator = Global> { pub(in ::collections::hash::map) base: RustcVacantEntry<'a, K, V, A> }

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

Fields

base: RustcVacantEntry<'a, K, V, A>

Implementations

impl<'a, K: 'a, V: 'a, A: Allocator> VacantEntry<'a, K, V, A>

fn key(&self) -> &K

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

Examples

use std::collections::HashMap;

let mut map: HashMap<&str, u32> = HashMap::new();
assert_eq!(map.entry("poneyland").key(), &"poneyland");

fn into_key(self) -> K

Take ownership of the key.

Examples

use std::collections::HashMap;
use std::collections::hash_map::Entry;

let mut map: HashMap<&str, u32> = HashMap::new();

if let Entry::Vacant(v) = map.entry("poneyland") {
    v.into_key();
}

fn insert(self, value: V) -> &'a mut V

Sets the value of the entry with the VacantEntry's key, and returns a mutable reference to it.

Examples

use std::collections::HashMap;
use std::collections::hash_map::Entry;

let mut map: HashMap<&str, u32> = HashMap::new();

if let Entry::Vacant(o) = map.entry("poneyland") {
    o.insert(37);
}
assert_eq!(map["poneyland"], 37);

fn insert_entry(self, value: V) -> OccupiedEntry<'a, K, V, A>

Sets the value of the entry with the VacantEntry's key, and returns an OccupiedEntry.

Examples

use std::collections::HashMap;
use std::collections::hash_map::Entry;

let mut map: HashMap<&str, u32> = HashMap::new();

if let Entry::Vacant(o) = map.entry("poneyland") {
    o.insert_entry(37);
}
assert_eq!(map["poneyland"], 37);

Trait Implementations

impl<K: Debug, V, A: Allocator> Debug for VacantEntry<'_, K, V, A>

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

Auto Trait Implementations

impl<'a, K, V, A = Global> !UnwindSafe for VacantEntry<'a, K, V, A>

impl<'a, K, V, A> Freeze for VacantEntry<'a, K, V, A> where RustcVacantEntry<'a, K, V, A>: Freeze,

impl<'a, K, V, A> RefUnwindSafe for VacantEntry<'a, K, V, A> where RustcVacantEntry<'a, K, V, A>: RefUnwindSafe,

impl<'a, K, V, A> Send for VacantEntry<'a, K, V, A> where RustcVacantEntry<'a, K, V, A>: Send,

impl<'a, K, V, A> Sync for VacantEntry<'a, K, V, A> where RustcVacantEntry<'a, K, V, A>: Sync,

impl<'a, K, V, A> Unpin for VacantEntry<'a, K, V, A> where RustcVacantEntry<'a, K, V, A>: Unpin,

impl<'a, K, V, A> UnsafeUnpin for VacantEntry<'a, K, V, A> where RustcVacantEntry<'a, K, V, A>: UnsafeUnpin,

Blanket Implementations

impl<T> Any for VacantEntry<'a, K, V, A> where T: 'static + ?Sized,

fn type_id(&self) -> TypeId

impl<T> Borrow<T> for VacantEntry<'a, K, V, A> where T: ?Sized,

fn borrow(&self) -> &T

impl<T> BorrowMut<T> for VacantEntry<'a, K, V, A> where T: ?Sized,

fn borrow_mut(&mut self) -> &mut T

impl<T> From<T> for VacantEntry<'a, K, V, A>

fn from(t: T) -> T

Returns the argument unchanged.

impl<T> SizeHint for VacantEntry<'a, K, V, A> where T: ?Sized,

fn lower_bound(&self) -> usize
fn upper_bound(&self) -> Option<usize>

impl<T> SizedTypeProperties for VacantEntry<'a, K, V, A>

impl<T, U> Into<U> for VacantEntry<'a, K, V, A> where U: From<T>,

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of [From]<T> for U chooses to do.

impl<T, U> TryFrom<U> for VacantEntry<'a, K, V, A> where U: Into<T>,

type Error = Infallible;
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

impl<T, U> TryInto<U> for VacantEntry<'a, K, V, A> where U: TryFrom<T>,

type Error = <U as TryFrom<T>>::Error;
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>