An unordered hash-table based Set implementation.
The elements of a HashSet
must have consistent equality
and hashCode implementations. This means that the equals operation
must define a stable equivalence relation on the elements (reflexive,
symmetric, transitive, and consistent over time), and that the hashCode
must consistent with equality, so that the same for objects that are
considered equal.
The set allows null
as an element.
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.
The iteration order of the set is not specified and depends on the hashcodes of the provided elements. However, the order is stable: multiple iterations over the same set produce the same order, as long as the set is not modified.
- Implements
-
- Set<E>
- Implemented by
Constructors
- HashSet({bool equals(E e1, E e2), int hashCode(E e), bool isValidKey(potentialKey) })
-
Create a hash set using the provided
equals
as equality.factory - HashSet.from(Iterable elements)
-
Create a hash set containing all
elements
.factory - HashSet.identity()
-
Creates an unordered identity-based set.
factory
Properties
- first → E
-
Returns the first element.
read-only, inherited - hashCode → int
-
Get a hash code for this object.
read-only, inherited - isEmpty → bool
-
Returns
true
if there are no elements in this collection.read-only, inherited - isNotEmpty → bool
-
Returns true if there is at least one element in this collection.
read-only, inherited - iterator → Iterator<E>
-
Provides an iterator that iterates over the elements of this set.
read-only - last → E
-
Returns the last element.
read-only, inherited - length → int
-
Returns the number of elements in the iterable.
read-only, inherited - runtimeType → Type
-
A representation of the runtime type of the object.
read-only, inherited - single → E
-
Checks that this iterable has only one element, and returns that element.
read-only, inherited
Operators
-
operator ==(
other) → bool -
The equality operator.
inherited
Methods
-
add(
E value) → bool -
Adds
value
to the set.inherited -
addAll(
Iterable<E> elements) → void -
Adds all
elements
to this Set.inherited -
any(
bool f(E element)) → bool -
Checks whether any element of this iterable satisfies
test
.inherited -
clear(
) → void -
Removes all elements in the set.
inherited -
contains(
Object value) → bool -
Returns true if
value
is in the set.inherited -
containsAll(
Iterable<Object> other) → bool -
Returns whether this Set contains all the elements of
other
.inherited -
difference(
Set<Object> other) → Set<E> -
Returns a new set with the elements of this that are not in
other
.inherited -
elementAt(
int index) → E -
Returns the
index
th element.inherited -
every(
bool f(E element)) → bool -
Checks whether every element of this iterable satisfies
test
.inherited -
expand<T>(
Iterable<T> f(E element)) → Iterable<T> -
Expands each element of this Iterable into zero or more elements.
inherited -
firstWhere(
bool test(E element), { E orElse() }) → E -
Returns the first element that satisfies the given predicate
test
.inherited -
fold<T>(
T initialValue, T combine(T previousValue, E element)) → T -
Reduces a collection to a single value by iteratively combining each element of the collection with an existing value
inherited -
forEach(
void f(E element)) → void -
Applies the function
f
to each element of this collection in iteration order.inherited -
intersection(
Set<Object> other) → Set<E> -
Returns a new set which is the intersection between this set and
other
.inherited -
join(
[String separator = "" ]) → String -
Converts each element to a String and concatenates the strings.
inherited -
lastWhere(
bool test(E element), { E orElse() }) → E -
Returns the last element that satisfies the given predicate
test
.inherited -
lookup(
Object object) → E -
If an object equal to
object
is in the set, return it.inherited -
map<T>(
T f(E e)) → Iterable<T> -
Returns a new lazy Iterable with elements that are created by calling
f
on each element of thisIterable
in iteration order.inherited -
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a non-existent method or property is accessed.
inherited -
reduce(
E combine(E value, E element)) → E -
Reduces a collection to a single value by iteratively combining elements of the collection using the provided function.
inherited -
remove(
Object value) → bool -
Removes
value
from the set. Returns true ifvalue
was in the set. Returns false otherwise. The method has no effect ifvalue
value was not in the set.inherited -
removeAll(
Iterable<Object> elements) → void -
Removes each element of
elements
from this set.inherited -
removeWhere(
bool test(E element)) → void -
Removes all elements of this set that satisfy
test
.inherited -
retainAll(
Iterable<Object> elements) → void -
Removes all elements of this set that are not elements in
elements
.inherited -
retainWhere(
bool test(E element)) → void -
Removes all elements of this set that fail to satisfy
test
.inherited -
singleWhere(
bool test(E element)) → E -
Returns the single element that satisfies
test
.inherited -
skip(
int count) → Iterable<E> -
Returns an Iterable that provides all but the first
count
elements.inherited -
skipWhile(
bool test(E value)) → Iterable<E> -
Returns an
Iterable
that skips leading elements whiletest
is satisfied.inherited -
take(
int count) → Iterable<E> -
Returns a lazy iterable of the
count
first elements of this iterable.inherited -
takeWhile(
bool test(E value)) → Iterable<E> -
Returns a lazy iterable of the leading elements satisfying
test
.inherited -
toList(
{bool growable: true }) → List<E> -
Creates a List containing the elements of this Iterable.
inherited -
toSet(
) → Set<E> -
Creates a
Set
containing the same elements as this iterable.inherited -
toString(
) → String -
Returns a string representation of this object.
inherited -
union(
Set<E> other) → Set<E> -
Returns a new set which contains all the elements of this set and
other
.inherited -
where(
bool test(E element)) → Iterable<E> -
Returns a new lazy Iterable with all elements that satisfy the predicate
test
.inherited