Struct std::collections::hash_map::VacantEntry

1.0.0 · source ·
pub struct VacantEntry<'a, K: 'a, V: 'a> { /* private fields */ }
Expand description

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

Implementations§

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

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

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
source

pub fn insert_entry(self, value: V) -> OccupiedEntry<'a, K, V>

🔬This is a nightly-only experimental API. (entry_insert #65225)

Sets the value of the entry with the VacantEntry’s key, and returns an OccupiedEntry.

Examples
#![feature(entry_insert)]
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_entry(37);
}
assert_eq!(map["poneyland"], 37);
Run

Trait Implementations§

Formats the value using the given formatter. Read more

Auto Trait Implementations§

Blanket Implementations§

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.