dart:core
Set<E> class
A collection of objects in which each object can occur only once.
That is, for each object of the element type, the object is either considered to be in the set, or to not be in the set.
Set implementations may consider some elements indistinguishable. These elements are treated as being the same for any operation on the set.
The default Set implementation, LinkedHashSet, considers objects indistinguishable if they are equal with regard to operator Object.==.
Iterating over elements of a set may be either unordered or ordered in some way. Examples:
- A HashSet is unordered, which means that its iteration order is unspecified,
-
LinkedHashSet iterates in the insertion order of its elements, and
- a sorted set like SplayTreeSet iterates the elements in sorted order.
It is generally not allowed to modify the set (add or remove elements) while an operation on the set is being performed, for example during a call to forEach or containsAll. Nor is it allowed to modify the set while iterating either the set itself or any Iterable that is backed by the set, such as the ones returned by methods like where and map.
It is generally not allowed to modify the equality of elements (and thus not their hashcode) while they are in the set. Some specialized subtypes may be more permissive, in which case they should document this behavior.
- Inheritance
- Implemented by
Constructors
- Set()
factory
- Creates an empty Set. [...]
- Set.from(Iterable elements)
factory
- Creates a Set that contains all
elements. [...] - Set.identity()
factory
- Creates an empty identity Set. [...]
- Set.of(Iterable<E> elements)
factory
- Creates a Set from
elements. [...]
Properties
- iterator → Iterator<E>
read-only
- Provides an iterator that iterates over the elements of this set. [...]
- 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 this. [...]
- 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
- Adds
value to the set. [...] - addAll(Iterable<E> elements) → void
- Adds all
elements to this Set. [...] - cast<R>() → Set<R>
- Provides a view of this set as a set of
R instances. [...] - clear() → void
- Removes all elements in the set.
- contains(Object value) → bool
- Returns true if
value is in the set. - containsAll(Iterable<Object> other) → bool
- Returns whether this Set contains all the elements of
other. - difference(Set<Object> other) → Set<E>
- Returns a new set with the elements of this that are not in
other. [...] - intersection(Set<Object> other) → Set<E>
- Returns a new set which is the intersection between this set and
other. [...] - lookup(Object object) → E
- If an object equal to
object is in the set, return it. [...] - remove(Object value) → bool
- 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
- Removes each element of
elements from this set. - removeWhere(bool test(E element)) → void
- Removes all elements of this set that satisfy
test. - retainAll(Iterable<Object> elements) → void
- Removes all elements of this set that are not elements in
elements. [...] - retainWhere(bool test(E element)) → void
- Removes all elements of this set that fail to satisfy
test. - toSet() → Set<E>
- Creates a Set containing the same elements as this iterable. [...]
- union(Set<E> other) → Set<E>
- Returns a new set which contains all the elements of this set and
other. [...] - any(bool test(E element)) → bool
inherited
- Checks whether any element of this iterable satisfies
test. [...] - 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. [...] - forEach(void f(E element)) → void
inherited
- Applies the function
f to each element of this collection in iteration order. - 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. [...] - 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. [...]
- 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. [...]
- toString() → String
inherited
- Returns a string representation of (some of) the elements of
this. [...] - 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. [...]
Static Methods
- castFrom<S, T>(Set<S> source, { Set<R> newSet() }) → Set<T>
- Adapts
source to be a Set<T>. [...]