1.0.0[][src]Struct std::collections::btree_map::VacantEntry

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

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

Methods

impl<'a, K, V> VacantEntry<'a, K, V> where
    K: Ord
[src]

Important traits for &'_ mut I

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

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

Important traits for &'_ mut I

Sets the value of the entry with the VacantEntry's key, and returns a mutable reference to it.

Examples

use std::collections::BTreeMap;

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

// count the number of occurrences of letters in the vec
for x in vec!["a","b","a","c","a","b"] {
    *count.entry(x).or_insert(0) += 1;
}

assert_eq!(count["a"], 3);Run

Trait Implementations

impl<'a, K, V> Debug for VacantEntry<'a, K, V> where
    K: 'a + Ord + Debug,
    V: 'a, 
1.12.0
[src]

Formats the value using the given formatter. Read more

Auto Trait Implementations

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

Blanket Implementations

impl<T, U> TryFrom for T where
    T: From<U>, 
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🔬 This is a nightly-only experimental API. (try_from #33417)

The type returned in the event of a conversion error.

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

Performs the conversion.

impl<T> From for T
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Performs the conversion.

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

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

The type returned in the event of a conversion error.

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

Performs the conversion.

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

Performs the conversion.

impl<T> Borrow for T where
    T: ?Sized
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Important traits for &'_ mut I

Immutably borrows from an owned value. Read more

impl<T> BorrowMut for T where
    T: ?Sized
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Important traits for &'_ mut I

Mutably borrows from an owned value. Read more

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