dart:collection
HashMap<K, V> class
A hash-table based implementation of Map.
The keys of a HashMap must have consistent Object.== 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 iteration 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.
- Implemented types
-
Constructors
- HashMap({bool equals(K key1, K key2), int hashCode(K key), bool isValidKey(dynamic potentialKey) })
factory
- Creates an unordered hash-table based Map. [...]
- HashMap.from(Map other)
factory
- Creates a HashMap that contains all key/value pairs of
other. [...] - HashMap.fromEntries(Iterable<MapEntry<K, V>> entries)
factory
- Creates a HashMap containing the entries of
entries. [...] - HashMap.fromIterable(Iterable iterable, { K key(dynamic element), V value(dynamic element) })
factory
- Creates a HashMap where the keys and values are computed from the
iterable. [...] - HashMap.fromIterables(Iterable<K> keys, Iterable<V> values)
factory
- Creates a HashMap associating the given
keys to values. [...] - HashMap.identity()
factory
- Creates an unordered identity-based map. [...]
- HashMap.of(Map<K, V> other)
factory
- Creates a HashMap that contains all key/value pairs of
other.
Properties
- entries → Iterable<MapEntry<K, V>>
read-only, inherited
- The map entries of this.
- hashCode → int
read-only, inherited
- The hash code for this object. [...]
- 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.
- runtimeType → Type
read-only, inherited
- A representation of the runtime type of the object.
- values → Iterable<V>
read-only, inherited
- The values of this. [...]
Methods
- addAll(Map<K, V> other) → void
inherited
- Adds all key/value pairs of
other to this map. [...] - addEntries(Iterable<MapEntry<K, V>> newEntries) → void
inherited
- Adds all key/value pairs of
newEntries to this map. [...] - cast<RK, RV>() → Map<RK, RV>
inherited
- Provides a view of this map as having
RK keys and RV instances, if necessary. [...] - 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. [...] - map<K2, V2>(MapEntry<K2, V2> f(K key, V value)) → Map<K2, V2>
inherited
- Returns a new map where all entries of this map are transformed by the given
f function. - noSuchMethod(Invocation invocation) → dynamic
inherited
- Invoked when a non-existent method or property is accessed. [...]
- 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. [...] - removeWhere(bool predicate(K key, V value)) → void
inherited
- Removes all entries of this map that satisfy the given
predicate. - toString() → String
inherited
- Returns a string representation of this object.
- update(K key, V update(V value), { V ifAbsent() }) → V
inherited
- Updates the value for the provided
key. [...] - updateAll(V update(K key, V value)) → void
inherited
- Updates all values. [...]
Operators
- operator ==(dynamic other) → bool
inherited
- The equality operator. [...]
- 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. [...]