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 ==.
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
-
-
Map<
K, V>
-
Map<
Constructors
- HashMap({bool equals(K, K), int hashCode(K), bool isValidKey(dynamic)}) 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< entries)K, V> >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
keystovalues. [...] - 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
- Whether there is no key/value pair in the map.
- isNotEmpty → bool read-only, inherited
- Whether 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) → voidinherited - Adds all key/value pairs of
otherto this map. [...] - addEntries(
Iterable< MapEntry< newEntries) → voidK, V> >inherited - Adds all key/value pairs of
newEntriesto this map. [...] - cast<
RK, RV> () → Map< RK, RV> inherited - Provides a view of this map as having
RKkeys andRVinstances, if necessary. [...] - clear(
) → void inherited - Removes all entries from the map. [...]
- containsKey(
Object? key) → bool inherited - Whether this map contains the given
key. [...] - containsValue(
Object? value) → bool inherited - Whether this map contains the given
value. [...] - forEach(
void action(K key, V value)) → void inherited - Applies
actionto each key/value pair of the map. [...] - map<
K2, V2> (MapEntry< K2, V2> convert(K key, V value)) → Map<K2, V2> inherited - Returns a new map where all entries of this map are transformed by the given
convertfunction. - 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 entry if it isn't there. [...] - remove(
Object? key) → V? inherited - Removes
keyand its associated value, if present, from the map. [...] - removeWhere(
bool test(K key, V value)) → void inherited - Removes all entries of this map that satisfy the given
test. - toString(
) → String inherited - 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 ==(
Object other) → bool inherited - The equality operator. [...]
- operator [](
Object? key) → V? inherited - The value for the given
key, ornullifkeyis not in the map. [...] - operator []=(
K key, V value) → void inherited - Associates the
keywith the givenvalue. [...]
© 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
https://api.dart.dev/stable/2.13.0/dart-collection/HashMap-class.html