# 1.0.0[−][src]Struct std::collections::hash_map::VacantEntry

    pub struct VacantEntry<'a, K: 'a, V: 'a> { /* fields omitted */ }

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

## Methods

###

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

[src]

####
ⓘImportant traits for &'a mut I

### Important traits for &'a mut I

`impl<'a, I> Iterator for &'a mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'a, R: Read + ?Sized> Read for &'a mut Rimpl<'a, W: Write + ?Sized> Write for &'a mut W`

`pub fn key(&self) -> &K`

1.10.0
[src]

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

####

`pub fn into_key(self) -> K`

1.12.0
[src]

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

####
ⓘImportant traits for &'a mut I

### Important traits for &'a mut I

`impl<'a, I> Iterator for &'a mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'a, R: Read + ?Sized> Read for &'a mut Rimpl<'a, W: Write + ?Sized> Write for &'a mut W`

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

[src]

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

## Trait Implementations

###

`impl<'a, K: 'a + Debug, V: 'a> Debug for VacantEntry<'a, K, V>`

1.12.0
[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> !Send for VacantEntry<'a, K, V>`

###

`impl<'a, K, V> !Sync for VacantEntry<'a, K, V>`

## Blanket Implementations

###

`impl<T> From for T`

[src]

####

`fn from(t: T) -> T`

[src]

Performs the conversion.

###

`impl<T, U> TryFrom for T where T: From<U>,`

[src]

#### `type Error = !`

🔬 This is a nightly-only experimental API. (`try_from` #33417)

The type returned in the event of a conversion error.

####

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

[src]

🔬 This is a nightly-only experimental API. (`try_from` #33417)

Performs the conversion.

###

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

[src]

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

🔬 This is a nightly-only experimental API. (`try_from` #33417)

The type returned in the event of a conversion error.

####

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

[src]

🔬 This is a nightly-only experimental API. (`try_from` #33417)

Performs the conversion.

###

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

[src]

####

`fn into(self) -> U`

[src]

Performs the conversion.

###

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

[src]

####
ⓘImportant traits for &'a mut I

### Important traits for &'a mut I

`impl<'a, I> Iterator for &'a mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'a, R: Read + ?Sized> Read for &'a mut Rimpl<'a, W: Write + ?Sized> Write for &'a mut W`

`fn borrow(&self) -> &T`

[src]

Immutably borrows from an owned value. Read more

###

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

[src]

####
ⓘImportant traits for &'a mut I

### Important traits for &'a mut I

`impl<'a, I> Iterator for &'a mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'a, R: Read + ?Sized> Read for &'a mut Rimpl<'a, W: Write + ?Sized> Write for &'a 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 get_type_id(&self) -> TypeId`

[src]

🔬 This is a nightly-only experimental API. (`get_type_id` #27745)

this method will likely be replaced by an associated static

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

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