std::collections::hash_map::RawEntryMut - Rust
Description: API documentation for the Rust `RawEntryMut` enum in crate `std`.
Keywords: rust, rustlang, rust-lang, RawEntryMut

# [−][src]Enum std::collections::hash_map::RawEntryMut

    pub enum RawEntryMut<'a, K: 'a, V: 'a, S: 'a> {
        Occupied(RawOccupiedEntryMut<'a, K, V>),
        Vacant(RawVacantEntryMut<'a, K, V, S>),
    }

🔬 This is a nightly-only experimental API. (`hash_raw_entry` #56167)

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

This is a lower-level version of `Entry`.

This `enum` is constructed through the `raw_entry_mut` method on `HashMap`, then calling one of the methods of that `RawEntryBuilderMut`.

## Variants

`Occupied(RawOccupiedEntryMut<'a, K, V>)`
🔬 This is a nightly-only experimental API. (`hash_raw_entry` #56167)

An occupied entry.

`Vacant(RawVacantEntryMut<'a, K, V, S>)`
🔬 This is a nightly-only experimental API. (`hash_raw_entry` #56167)

A vacant entry.

## Methods

### `impl<'a, K, V, S> RawEntryMut<'a, K, V, S>`[src]

#### `pub fn or_insert(self, default_key: K, default_val: V) -> (&'a mut K, &'a mut V) where
K: Hash,
S: BuildHasher,` [src]

🔬 This is a nightly-only experimental API. (`hash_raw_entry` #56167)

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

# Examples

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

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

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

    *map.raw_entry_mut().from_key("poneyland").or_insert("poneyland", 10).1 *= 2;
    assert_eq!(map["poneyland"], 6);Run

#### `pub fn or_insert_with<F>(self, default: F) -> (&'a mut K, &'a mut V) where
F: FnOnce() -> (K, V),
K: Hash,
S: BuildHasher,` [src]

🔬 This is a nightly-only experimental API. (`hash_raw_entry` #56167)

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

# Examples

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

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

    map.raw_entry_mut().from_key("poneyland").or_insert_with(|| {
        ("poneyland", "hoho".to_string())
    });

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

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

🔬 This is a nightly-only experimental API. (`hash_raw_entry` #56167)

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

# Examples

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

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

    map.raw_entry_mut()
       .from_key("poneyland")
       .and_modify(|_k, v| { *v += 1 })
       .or_insert("poneyland", 42);
    assert_eq!(map["poneyland"], 42);

    map.raw_entry_mut()
       .from_key("poneyland")
       .and_modify(|_k, v| { *v += 1 })
       .or_insert("poneyland", 0);
    assert_eq!(map["poneyland"], 43);Run

## Trait Implementations

### `impl<K: Debug, V: Debug, S, '_> Debug for RawEntryMut<'_, K, V, S>`[src]

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

Formats the value using the given formatter. Read more

## Auto Trait Implementations

### `impl<'a, K, V, S> Send for RawEntryMut<'a, K, V, S> where
K: Send,
S: Sync,
V: Send,`

### `impl<'a, K, V, S> !Sync for RawEntryMut<'a, K, V, S>`

## Blanket Implementations

### `impl<T, U> TryFrom<U> 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<U>>::Error>`[src]

Performs the conversion.

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

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

Performs the conversion.

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

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

Performs the conversion.

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

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

The type returned in the event of a conversion error.

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

Performs the conversion.

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

####
ⓘImportant traits for &'_ mut I

### Important traits for &'_ mut I

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

Immutably borrows from an owned value. Read more

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

####
ⓘImportant traits for &'_ mut I

### Important traits for &'_ mut I

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

Mutably borrows from an owned value. Read more

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

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

Gets the `TypeId` of `self`. Read more

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