Struct std::collections::hash_map::VacantEntry

1.0.0 · source ·
pub struct VacantEntry<'a, K: 'a, V: 'a> { /* private fields */ }
Expand description

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

Implementations§

source§

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

1.10.0 · source

pub 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");
Run
1.12.0 · source

pub 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();
}
Run
source

pub 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);
Run
source

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

🔬This is a nightly-only experimental API. (entry_insert #65225)

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

Examples
#![feature(entry_insert)]
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);
Run

Trait Implementations§

1.12.0 · source§

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

source§

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

Formats the value using the given formatter. Read more

Auto Trait Implementations§

§

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

§

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

§

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

§

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

§

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

Blanket Implementations§

source§

impl<T> Any for Twhere
    T: 'static + ?Sized,

source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
source§

impl<T> Borrow<T> for Twhere
    T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
source§

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
source§

impl<T> From<T> for T

const: unstable · source§

fn from(t: T) -> T

Returns the argument unchanged.

source§

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.

source§

impl<T, U> TryFrom<U> for Twhere
    U: Into<T>,

§

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.
source§

impl<T, U> TryInto<U> for Twhere
    U: TryFrom<T>,

§

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.