VacantEntry in alloc::collections::btree_map - Rust
Description: A view into a vacant entry in a `BTreeMap`. It is part of the [`Entry`] enum.
Keywords: rust, rustlang, rust-lang, VacantEntry

# Struct alloc::collections::btree_map::VacantEntry
1.0.0[−][src]

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

Expand description

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

## Implementations

[src]

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

1.10.0[src]

#### 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::BTreeMap;

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

Run
1.12.0[src]

#### pub fn into_key(self) -> K

Take ownership of the key.

# Examples

    use std::collections::BTreeMap;
    use std::collections::btree_map::Entry;

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

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

Run
[src]

#### 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::BTreeMap;
    use std::collections::btree_map::Entry;

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

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

Run

## Trait Implementations

1.12.0[src]

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

[src]

#### 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

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

[src]

#### pub fn type_id(&self) -> TypeId

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

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

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#### pub fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

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

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

Mutably borrows from an owned value. Read more

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### impl<T> From<T> for T

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#### pub fn from(t: T) -> T

Performs the conversion.

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

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#### pub fn into(self) -> U

Performs the conversion.

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### impl<T, U> TryFrom<U> for T where
U: Into<T>,

#### type Error = Infallible

The type returned in the event of a conversion error.

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

Performs the conversion.

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

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

The type returned in the event of a conversion error.

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

Performs the conversion.