Struct std::collections::btree_map::VacantEntry

1.0.0 · source ·
pub struct VacantEntry<'a, K, V, A = Global>where
    A: Allocator + Clone,
{ /* private fields */ }
Expand description

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

Implementations§

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impl<'a, K, V, A> VacantEntry<'a, K, V, A>where
    K: Ord,
    A: Allocator + Clone,

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::BTreeMap;

let mut map: BTreeMap<&str, usize> = BTreeMap::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::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
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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 · source§

impl<K, V, A> Debug for VacantEntry<'_, K, V, A>where
    K: Debug + Ord,
    A: Allocator + Clone,

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

Formats the value using the given formatter. Read more

Auto Trait Implementations§

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

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

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

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

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

Blanket Implementations§

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

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere
    T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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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
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impl<T> From<T> for T

const: unstable · source§

fn from(t: T) -> T

Returns the argument unchanged.

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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.

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

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

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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.