HashMap::insert

pub fn insert(K k, V v) -> bool

use collections::map::{HashMap};

Stores v under k, replacing any value already there.

Returns true when k is new and false when an existing value was replaced.

Called on a HashMap value as value.insert(…).

Parameters#

Returns#

bool

Contracts#

Checked according to --contracts (see Contracts).

ensures !result || self.len == old(self.len) + 1
ensures result || self.len == old(self.len)

Examples#

use collections::map::{HashMap};
use tests::assert;
let m: HashMap<string, int> = HashMap::new();
assert!(m.insert("a", 1));
assert!(!m.insert("a", 2));
assert!(m.get_or("a", 0) == 2);

See also#

• HashMap: A hash map from keys of type K to values of type V.
• HashMap::with_capacity: Creates an empty map with room for about cap buckets before it grows.
• HashMap::new: Creates an empty map.
• HashMap::size: Returns the number of entries.
• HashMap::is_empty: Returns true when the map has no entries.
• HashMap::capacity: Returns the number of buckets.
• HashMap::clear: Removes every entry, keeping the bucket count.
• HashMap::keys: Returns the keys, in insertion order.