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Enum std::collections::hash_map::Entry

pub enum Entry<'a, K: 'a, V: 'a> {
    Occupied(OccupiedEntry<'a, K, V>),
    Vacant(VacantEntry<'a, K, V>),
}

A view into a single entry in a map, which may either be vacant or occupied.

This enum is constructed from the entry method on HashMap.

Variants

Occupied(OccupiedEntry<'a, K, V>)

An occupied entry.

Vacant(VacantEntry<'a, K, V>)

A vacant entry.

Implementations

`impl<'a, K, V> Entry<'a, K, V>`[src]

pub fn or_insert(self, default: V) -> &'a mut VⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
    F: Unpin + Future + ?Sized, 
    type Output = <F as Future>::Output;
impl<'_, I> Iterator for &'_ mut I where
    I: Iterator + ?Sized, 
    type Item = <I as Iterator>::Item;
impl<R: Read + ?Sized, '_> Read for &'_ mut R
impl<W: Write + ?Sized, '_> Write for &'_ mut W

[src]

Ensures a value is in the entry by inserting the default if empty, and returns a mutable reference to the value in the entry.

Examples

use std::collections::HashMap;

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

map.entry("poneyland").or_insert(3);
assert_eq!(map["poneyland"], 3);

*map.entry("poneyland").or_insert(10) *= 2;
assert_eq!(map["poneyland"], 6);

pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut VⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
    F: Unpin + Future + ?Sized, 
    type Output = <F as Future>::Output;
impl<'_, I> Iterator for &'_ mut I where
    I: Iterator + ?Sized, 
    type Item = <I as Iterator>::Item;
impl<R: Read + ?Sized, '_> Read for &'_ mut R
impl<W: Write + ?Sized, '_> Write for &'_ mut W

[src]

Ensures a value is in the entry by inserting the result of the default function if empty, and returns a mutable reference to the value in the entry.

Examples

use std::collections::HashMap;

let mut map: HashMap<&str, String> = HashMap::new();
let s = "hoho".to_string();

map.entry("poneyland").or_insert_with(|| s);

assert_eq!(map["poneyland"], "hoho".to_string());

pub fn or_insert_with_key<F: FnOnce(&K) -> V>(self, default: F) -> &'a mut VⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
    F: Unpin + Future + ?Sized, 
    type Output = <F as Future>::Output;
impl<'_, I> Iterator for &'_ mut I where
    I: Iterator + ?Sized, 
    type Item = <I as Iterator>::Item;
impl<R: Read + ?Sized, '_> Read for &'_ mut R
impl<W: Write + ?Sized, '_> Write for &'_ mut W

[src]

🔬 This is a nightly-only experimental API. (or_insert_with_key #71024)

Ensures a value is in the entry by inserting, if empty, the result of the default function, which takes the key as its argument, and returns a mutable reference to the value in the entry.

Examples

#![feature(or_insert_with_key)]
use std::collections::HashMap;

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

map.entry("poneyland").or_insert_with_key(|key| key.chars().count());

assert_eq!(map["poneyland"], 9);

pub fn key(&self) -> &KⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
    F: Unpin + Future + ?Sized, 
    type Output = <F as Future>::Output;
impl<'_, I> Iterator for &'_ mut I where
    I: Iterator + ?Sized, 
    type Item = <I as Iterator>::Item;
impl<R: Read + ?Sized, '_> Read for &'_ mut R
impl<W: Write + ?Sized, '_> Write for &'_ mut W

[src]1.10.0

Returns a reference to this entry's key.

Examples

use std::collections::HashMap;

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

`pub fn and_modify<F>(self, f: F) -> Self where F: FnOnce(&mut V),` [src]1.26.0

Provides in-place mutable access to an occupied entry before any potential inserts into the map.

Examples

use std::collections::HashMap;

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

map.entry("poneyland")
   .and_modify(|e| { *e += 1 })
   .or_insert(42);
assert_eq!(map["poneyland"], 42);

map.entry("poneyland")
   .and_modify(|e| { *e += 1 })
   .or_insert(42);
assert_eq!(map["poneyland"], 43);

`pub fn insert(self, value: V) -> OccupiedEntry<'a, K, V>`[src]

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

Sets the value of the entry, and returns an OccupiedEntry.

Examples

#![feature(entry_insert)]
use std::collections::HashMap;

let mut map: HashMap<&str, String> = HashMap::new();
let entry = map.entry("poneyland").insert("hoho".to_string());

assert_eq!(entry.key(), &"poneyland");

`impl<'a, K, V: Default> Entry<'a, K, V>`[src]

pub fn or_default(self) -> &'a mut VⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
    F: Unpin + Future + ?Sized, 
    type Output = <F as Future>::Output;
impl<'_, I> Iterator for &'_ mut I where
    I: Iterator + ?Sized, 
    type Item = <I as Iterator>::Item;
impl<R: Read + ?Sized, '_> Read for &'_ mut R
impl<W: Write + ?Sized, '_> Write for &'_ mut W

[src]1.28.0

Ensures a value is in the entry by inserting the default value if empty, and returns a mutable reference to the value in the entry.

Examples

use std::collections::HashMap;

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

assert_eq!(map["poneyland"], None);

Trait Implementations

`impl<K: Debug, V: Debug, '_> Debug for Entry<'_, K, V>`[src]1.12.0

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

Auto Trait Implementations

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

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

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

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

`impl<'a, K, V> !UnwindSafe for Entry<'a, K, V>`

Blanket Implementations

`impl<T> Any for T where T: 'static + ?Sized,` [src]

`fn type_id(&self) -> TypeId`[src]

`impl<T> Borrow<T> for T where T: ?Sized,` [src]

fn borrow(&self) -> &TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
    F: Unpin + Future + ?Sized, 
    type Output = <F as Future>::Output;
impl<'_, I> Iterator for &'_ mut I where
    I: Iterator + ?Sized, 
    type Item = <I as Iterator>::Item;
impl<R: Read + ?Sized, '_> Read for &'_ mut R
impl<W: Write + ?Sized, '_> Write for &'_ mut W

[src]

`impl<T> BorrowMut<T> for T where T: ?Sized,` [src]

fn borrow_mut(&mut self) -> &mut TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
    F: Unpin + Future + ?Sized, 
    type Output = <F as Future>::Output;
impl<'_, I> Iterator for &'_ mut I where
    I: Iterator + ?Sized, 
    type Item = <I as Iterator>::Item;
impl<R: Read + ?Sized, '_> Read for &'_ mut R
impl<W: Write + ?Sized, '_> Write for &'_ mut W

[src]

`impl<T> From<T> for T`[src]

`fn from(t: T) -> T`[src]

`impl<T, U> Into for T where U: From<T>,` [src]

`fn into(self) -> U`[src]

`impl<T, U> TryFrom for T where U: Into<T>,` [src]

`type Error = Infallible`

The type returned in the event of a conversion error.

`fn try_from(value: U) -> Result<T, <T as TryFrom>::Error>`[src]

`impl<T, U> TryInto for T where U: TryFrom<T>,` [src]

`type Error = >::Error`

The type returned in the event of a conversion error.

`fn try_into(self) -> Result<U, >::Error>`[src]

© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/collections/hash_map/enum.Entry.html

Enum std::collections::hash_map::Entry

Variants

Implementations

impl<'a, K, V> Entry<'a, K, V>[src]

Notable traits for &'_ mut F

Examples

Notable traits for &'_ mut F

Examples

Notable traits for &'_ mut F

Examples

Notable traits for &'_ mut F

Examples

pub fn and_modify<F>(self, f: F) -> Self where F: FnOnce(&mut V), [src]1.26.0

Examples

pub fn insert(self, value: V) -> OccupiedEntry<'a, K, V>[src]

Examples

impl<'a, K, V: Default> Entry<'a, K, V>[src]

Notable traits for &'_ mut F

Examples

Trait Implementations

impl<K: Debug, V: Debug, '_> Debug for Entry<'_, K, V>[src]1.12.0

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

Auto Trait Implementations

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

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

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

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

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

Blanket Implementations

impl<T> Any for T where T: 'static + ?Sized, [src]

fn type_id(&self) -> TypeId[src]

impl<T> Borrow<T> for T where T: ?Sized, [src]

Notable traits for &'_ mut F

impl<T> BorrowMut<T> for T where T: ?Sized, [src]

Notable traits for &'_ mut F

impl<T> From<T> for T[src]

fn from(t: T) -> T[src]

impl<T, U> Into<U> for T where U: From<T>, [src]

fn into(self) -> U[src]

impl<T, U> TryFrom<U> for T where U: Into<T>, [src]

type Error = Infallible

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>[src]

impl<T, U> TryInto<U> for T where U: TryFrom<T>, [src]

type Error = <U as TryFrom<T>>::Error

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>[src]

`impl<'a, K, V> Entry<'a, K, V>`[src]

`pub fn and_modify<F>(self, f: F) -> Self where F: FnOnce(&mut V),` [src]1.26.0

`pub fn insert(self, value: V) -> OccupiedEntry<'a, K, V>`[src]

`impl<'a, K, V: Default> Entry<'a, K, V>`[src]

`impl<K: Debug, V: Debug, '_> Debug for Entry<'_, K, V>`[src]1.12.0

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

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

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

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

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

`impl<'a, K, V> !UnwindSafe for Entry<'a, K, V>`

`impl<T> Any for T where T: 'static + ?Sized,` [src]

`fn type_id(&self) -> TypeId`[src]

`impl<T> Borrow<T> for T where T: ?Sized,` [src]

`impl<T> BorrowMut<T> for T where T: ?Sized,` [src]

`impl<T> From<T> for T`[src]

`fn from(t: T) -> T`[src]

`impl<T, U> Into<U> for T where U: From<T>,` [src]

`fn into(self) -> U`[src]

`impl<T, U> TryFrom<U> for T where U: Into<T>,` [src]

`type Error = Infallible`

`fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>`[src]

`impl<T, U> TryInto<U> for T where U: TryFrom<T>,` [src]

`type Error = <U as TryFrom<T>>::Error`

`fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>`[src]