A hash-table based implementation of Map.

The keys of a HashMap must have consistent Object.operator== and Object.hashCode implementations. This means that the == operator must define a stable equivalence relation on the keys (reflexive, symmetric, transitive, and consistent over time), and that hashCode must be the same for objects that are considered equal by ==.

The map allows null as a key.

Iterating the map's keys, values or entries (through forEach) may happen in any order. The itearation order only changes when the map is modified. Values are iterated in the same order as their associated keys, so iterating the keys and values in parallel will give matching key and value pairs.

Implements
Implemented by

Properties

isEmpty → bool
read-only, inherited

Returns true if there is no key-value pair in the map.

isNotEmpty → bool
read-only, inherited

Returns true if there is at least one key-value pair in the map.

keys → Iterable<K>
read-only, inherited

The keys of this.…

length → int
read-only, inherited

The number of key-value pairs in the map.

values → Iterable<V>
read-only, inherited

The values of this.…

Constructors

HashMap({bool equals(K key1, K key2), int hashCode(K key), bool isValidKey(potentialKey)})

Creates an unordered hash-table based Map.…

HashMap.from(Map other)

Creates a HashMap that contains all key/value pairs of other.

HashMap.fromIterable(Iterable iterable, {K key(element), V value(element)})

Creates a HashMap where the keys and values are computed from the iterable.…

HashMap.fromIterables(Iterable<K> keys, Iterable<V> values)

Creates a HashMap associating the given keys to values.…

HashMap.identity()

Creates an unordered identity-based map.…

Operators

operator [](Object key) → V
inherited

Returns the value for the given key or null if key is not in the map.…

operator []=(K key, V value) → void
inherited

Associates the key with the given value.…

Methods

addAll(Map<K,V> other) → void
inherited

Adds all key-value pairs of other to this map.…

clear() → void
inherited

Removes all pairs from the map.…

containsKey(Object key) → bool
inherited

Returns true if this map contains the given key.…

containsValue(Object value) → bool
inherited

Returns true if this map contains the given value.…

forEach(void f(K key, V value)) → void
inherited

Applies f to each key-value pair of the map.…

putIfAbsent(K key, V ifAbsent()) → V
inherited

Look up the value of key, or add a new value if it isn't there.…

remove(Object key) → V
inherited

Removes key and its associated value, if present, from the map.…