LinkedHashSet<E> class
A LinkedHashSet is a hash-table based Set implementation.
The LinkedHashSet also keep track of the order that elements were inserted in, and iteration happens in first-to-last insertion order.
The elements of a LinkedHashSet must have consistent Object.== and Object.hashCode implementations. This means that the == operator must define a stable equivalence relation on the elements (reflexive, symmetric, transitive, and consistent over time), and that hashCode must be the same for objects that are considered equal by ==.
Iteration of elements is done in element insertion order. An element that was added after another will occur later in the iteration. Adding an element that is already in the set does not change its position in the iteration order, but removing an element and adding it again, will make it the last element of an iteration.
Most simple operations on HashSet are done in (potentially amortized) constant time: add, contains, remove, and length, provided the hash codes of objects are well distributed..
- Implemented types
-
-
Set<
E>
-
Set<
Constructors
- LinkedHashSet({bool equals(E, E), int hashCode(E), bool isValidKey(dynamic)}) factory
- Create an insertion-ordered hash set using the provided
equalsandhashCode. [...] - LinkedHashSet.from(Iterable elements) factory
- Create a linked hash set containing all
elements. [...] - LinkedHashSet.identity() factory
- Creates an insertion-ordered identity-based set. [...]
- LinkedHashSet.of(Iterable<
E> elements)factory - Create a linked hash set from
elements. [...]
Properties
- first → E read-only, inherited
- Returns the first element. [...]
- hashCode → int read-only, inherited
- The hash code for this object. [...]
- isEmpty → bool read-only, inherited
- Returns
trueif there are no elements in this collection. [...] - isNotEmpty → bool read-only, inherited
- Returns true if there is at least one element in this collection. [...]
- iterator → Iterator<
E> read-only, override - Provides an iterator that iterates over the elements in insertion order.
- last → E read-only, inherited
- Returns the last element. [...]
- length → int read-only, inherited
- Returns the number of elements in the iterable. [...]
- runtimeType → Type read-only, inherited
- A representation of the runtime type of the object.
- single → E read-only, inherited
- Checks that this iterable has only one element, and returns that element. [...]
Methods
- add(
E value) → bool inherited - Adds
valueto the set. [...] - addAll(
Iterable< E> elements) → voidinherited - Adds all
elementsto this set. [...] - any(
bool test(E element)) → bool inherited - Checks whether any element of this iterable satisfies
test. [...] - cast<
R> () → Set< R> inherited - Provides a view of this set as a set of
Rinstances. [...] - clear(
) → void inherited - Removes all elements from the set.
- contains(
Object? value) → bool inherited - Whether
valueis in the set. - containsAll(
Iterable< Object?> other) → boolinherited - Whether this set contains all the elements of
other. - difference(
Set< Object?> other) → Set<E> inherited - Creates a new set with the elements of this that are not in
other. [...] - elementAt(
int index) → E inherited - Returns the
indexth element. [...] - every(
bool test(E element)) → bool inherited - Checks whether every element of this iterable satisfies
test. [...] - expand<
T> (Iterable< T> f(E element)) → Iterable<T> inherited - Expands each element of this Iterable into zero or more elements. [...]
- firstWhere(
bool test(E element), {E orElse()}) → E inherited - Returns the first element that satisfies the given predicate
test. [...] - fold<
T> (T initialValue, T combine(T previousValue, E element)) → T inherited - Reduces a collection to a single value by iteratively combining each element of the collection with an existing value [...]
- followedBy(
Iterable< E> other) → Iterable<E> inherited - Returns the lazy concatenation of this iterable and
other. [...] - forEach(
void action(E element)) → void override - Executes a function on each element of the set. [...]
- intersection(
Set< Object?> other) → Set<E> inherited - Creates a new set which is the intersection between this set and
other. [...] - join(
[String separator = ""]) → String inherited - Converts each element to a String and concatenates the strings. [...]
- lastWhere(
bool test(E element), {E orElse()}) → E inherited - Returns the last element that satisfies the given predicate
test. [...] - lookup(
Object? object) → E? inherited - If an object equal to
objectis in the set, return it. [...] - map<
T> (T f(E e)) → Iterable< T> inherited - Returns a new lazy Iterable with elements that are created by calling
fon each element of thisIterablein iteration order. [...] - noSuchMethod(
Invocation invocation) → dynamic inherited - Invoked when a non-existent method or property is accessed. [...]
- reduce(
E combine(E value, E element)) → E inherited - Reduces a collection to a single value by iteratively combining elements of the collection using the provided function. [...]
- remove(
Object? value) → bool inherited - Removes
valuefrom the set. [...] - removeAll(
Iterable< Object?> elements) → voidinherited - Removes each element of
elementsfrom this set. - removeWhere(
bool test(E element)) → void inherited - Removes all elements of this set that satisfy
test. - retainAll(
Iterable< Object?> elements) → voidinherited - Removes all elements of this set that are not elements in
elements. [...] - retainWhere(
bool test(E element)) → void inherited - Removes all elements of this set that fail to satisfy
test. - singleWhere(
bool test(E element), {E orElse()}) → E inherited - Returns the single element that satisfies
test. [...] - skip(
int count) → Iterable< E> inherited - Returns an Iterable that provides all but the first
countelements. [...] - skipWhile(
bool test(E value)) → Iterable< E> inherited - Returns an
Iterablethat skips leading elements whiletestis satisfied. [...] - take(
int count) → Iterable< E> inherited - Returns a lazy iterable of the
countfirst elements of this iterable. [...] - takeWhile(
bool test(E value)) → Iterable< E> inherited - Returns a lazy iterable of the leading elements satisfying
test. [...] - toList(
{bool growable = true}) → List< E> inherited - Creates a List containing the elements of this Iterable. [...]
- toSet(
) → Set< E> inherited - Creates a Set with the same elements and behavior as this
Set. [...] - toString(
) → String inherited - A string representation of this object. [...]
- union(
Set< E> other) → Set<E> inherited - Creates a new set which contains all the elements of this set and
other. [...] - where(
bool test(E element)) → Iterable< E> inherited - Returns a new lazy Iterable with all elements that satisfy the predicate
test. [...] - whereType<
T> () → Iterable< T> inherited - Returns a new lazy Iterable with all elements that have type
T. [...]
Operators
- operator ==(
Object other) → bool inherited - The equality operator. [...]
© 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/LinkedHashSet-class.html