Enum std::collections::hash_map::Entry1.0.0 [] [src]

pub enum Entry<'a, K: 'a, V: 'a> {
    Occupied(OccupiedEntry<'a, K, V>),
    Vacant(VacantEntry<'a, K, V>),
}

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

This enum is constructed from the entry method on HashMap.

Variants

An occupied entry.

A vacant entry.

Methods

impl<'a, K, V> Entry<'a, K, V>
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Ensures a value is in the entry by inserting the default if empty, and returns a mutable reference to the value in the entry.

Examples

use std::collections::HashMap;

let mut map: HashMap<&str, u32> = HashMap::new();
map.entry("poneyland").or_insert(12);

assert_eq!(map["poneyland"], 12);

*map.entry("poneyland").or_insert(12) += 10;
assert_eq!(map["poneyland"], 22);Run

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

Examples

use std::collections::HashMap;

let mut map: HashMap<&str, String> = HashMap::new();
let s = "hoho".to_string();

map.entry("poneyland").or_insert_with(|| s);

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

Returns a reference to this entry's key.

Examples

use std::collections::HashMap;

let mut map: HashMap<&str, u32> = HashMap::new();
assert_eq!(map.entry("poneyland").key(), &"poneyland");Run

Trait Implementations

impl<'a, K: 'a + Debug, V: 'a + Debug> Debug for Entry<'a, K, V>
1.12.0
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Formats the value using the given formatter.

impl<'a, K, V> Placer<V> for Entry<'a, K, V>
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🔬 This is a nightly-only experimental API. (placement_new_protocol #27779)

Place is the intermedate agent guarding the uninitialized state for Data. Read more

🔬 This is a nightly-only experimental API. (placement_new_protocol #27779)

Creates a fresh place from self.