dart:collection
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 ==.
The set allows null as an element.
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
-
Constructors
- LinkedHashSet({bool equals(E e1, E e2), int hashCode(E e), bool isValidKey(dynamic potentialKey) })
factory
- Create an insertion-ordered hash set using the provided
equals and hashCode. [...] - 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
- iterator → Iterator<E>
read-only, override
- Provides an iterator that iterates over the elements in insertion order.
- 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
true if there are no elements in this collection. [...] - isNotEmpty → bool
read-only, inherited
- Returns true if there is at least one element in this collection. [...]
- 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
- forEach(void action(E element)) → void
override
- Executes a function on each element of the set. [...]
- add(E value) → bool
inherited
- Adds
value to the set. [...] - addAll(Iterable<E> elements) → void
inherited
- Adds all
elements to 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
R instances. [...] - clear() → void
inherited
- Removes all elements in the set.
- contains(Object value) → bool
inherited
- Returns true if
value is in the set. - containsAll(Iterable<Object> other) → bool
inherited
- Returns whether this Set contains all the elements of
other. - difference(Set<Object> other) → Set<E>
inherited
- Returns 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 concatentation of this iterable and
other. [...] - intersection(Set<Object> other) → Set<E>
inherited
- Returns 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
object is 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
f on each element of this Iterable in 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
value from the set. Returns true if value was in the set. Returns false otherwise. The method has no effect if value value was not in the set. - removeAll(Iterable<Object> elements) → void
inherited
- Removes each element of
elements from this set. - removeWhere(bool test(E element)) → void
inherited
- Removes all elements of this set that satisfy
test. - retainAll(Iterable<Object> elements) → void
inherited
- 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
count elements. [...] - skipWhile(bool test(E value)) → Iterable<E>
inherited
- Returns an
Iterable that skips leading elements while test is satisfied. [...] - take(int count) → Iterable<E>
inherited
- Returns a lazy iterable of the
count first 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 containing the same elements as this iterable. [...]
- toString() → String
inherited
- Returns a string representation of this object.
- union(Set<E> other) → Set<E>
inherited
- Returns 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 ==(dynamic other) → bool
inherited
- The equality operator. [...]