LinkedHashMap abstract class
A hash-table based implementation of Map.
The insertion order of keys is remembered, and keys are iterated in the order they were inserted into the map. Values are iterated in their corresponding key's order. Changing a key's value, when the key is already in the map, does not change the iteration order, but removing the key and adding it again will make it be last in the iteration order.
The keys of a LinkedHashMap 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.
- Implements
-
- HashMap<K, V>
Constructors
- LinkedHashMap({bool equals(K key1, K key2), int hashCode(K key), bool isValidKey(potentialKey) }) factory
-
Creates an insertion-ordered hash-table based Map.
- LinkedHashMap.from(Map other) factory
-
Creates a LinkedHashMap that contains all key value pairs of
other. - LinkedHashMap.fromIterable(Iterable iterable, { K key(element), V value(element) }) factory
-
Creates a LinkedHashMap where the keys and values are computed from the
iterable. - LinkedHashMap.fromIterables(Iterable<K> keys, Iterable<V> values) factory
-
Creates a LinkedHashMap associating the given
keystovalues. - LinkedHashMap.identity() factory
-
Creates an insertion-ordered identity-based map.
Properties
- 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.
Operators
- operator ==(
other) → bool inherited -
The equality operator.
- operator [](
Object key) → V inherited -
Returns the value for the given
keyor null ifkeyis not in the map. - operator []=(
K key, V value) → void inherited -
Associates the
keywith the givenvalue.
Methods
- addAll(
Map<K, V> other) → void inherited -
Adds all key-value pairs of
otherto 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
fto each key-value pair of the map. - 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
keyand its associated value, if present, from the map. - toString(
) → String inherited -
Returns a string representation of this object.
© 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
https://api.dartlang.org/stable/1.24.3/dart-collection/LinkedHashMap-class.html