MapKeySet<E> class
Null safety
An unmodifiable Set view of the keys of a Map.
The set delegates all operations to the underlying map.
A Map can only contain each key once, so its keys can always
be viewed as a Set without any loss, even if the Map.keys
getter only shows an Iterable view of the keys.
Note that lookup is not supported for this set.
- Mixed in types
- Available Extensions
Constructors
Properties
- first → E
-
Returns the first element.
read-onlyinherited
- hashCode → int
-
The hash code for this object.
read-onlyinherited
- isEmpty → bool
-
Whether this collection has no elements.
read-only
- isNotEmpty → bool
-
Whether this collection has at least one element.
read-only
-
iterator
→ Iterator<
E> -
Returns a new
Iteratorthat allows iterating the elements of thisIterable.read-onlyinherited - last → E
-
Returns the last element.
read-onlyinherited
- length → int
-
Returns the number of elements in this.
read-only
- runtimeType → Type
-
A representation of the runtime type of the object.
read-onlyinherited
- single → E
-
Checks that this iterable has only one element, and returns that element.
read-onlyinherited
Methods
-
add(
E value) → bool -
Throws an UnsupportedError;
operations that change the set are disallowed.
inherited
-
addAll(
Iterable< E> elements) → void -
Throws an UnsupportedError;
operations that change the set are disallowed.
inherited
-
any(
bool test(E)) → bool -
Checks whether any element of this iterable satisfies
test.inherited -
cast<
T> () → Set< T> -
Provides a view of this iterable as an iterable of
Rinstances. -
clear(
) → void -
Throws an UnsupportedError;
operations that change the set are disallowed.
inherited
-
contains(
Object? element) → bool -
Whether the collection contains an element equal to
element. -
containsAll(
Iterable< Object?> other) → bool -
Whether this set contains all the elements of
other.override -
difference(
Set< Object?> other) → Set<E> -
Returns a new set with the the elements of this that are not in
other.override -
elementAt(
int index) → E -
Returns the
indexth element.inherited -
every(
bool test(E)) → bool -
Checks whether every element of this iterable satisfies
test.inherited -
expand<
T> (Iterable< T> f(E)) → Iterable<T> -
Expands each element of this Iterable into zero or more elements.
inherited
-
firstWhere(
bool test(E), {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
-
followedBy(
Iterable< E> other) → Iterable<E> -
Returns the lazy concatenation of this iterable and
other.inherited -
forEach(
void f(E)) → void -
Invokes
actionon each element of this iterable in iteration order.inherited -
intersection(
Set< Object?> other) → Set<E> -
Returns a new set which is the intersection between this and
other.override -
join(
[String separator = '']) → String -
Converts each element to a String and concatenates the strings.
inherited
-
lastWhere(
bool test(E), {E orElse()?}) → E -
Returns the last element that satisfies the given predicate
test.inherited -
lookup(
Object? element) → E -
Throws an UnsupportedError since there's no corresponding method for
Maps.
override
-
map<
T> (T f(E)) → Iterable< T> -
The current elements of this iterable modified by
toElement.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 -
Throws an UnsupportedError;
operations that change the set are disallowed.
inherited
-
removeAll(
Iterable elements) → void -
Throws an UnsupportedError;
operations that change the set are disallowed.
inherited
-
removeWhere(
bool test(E)) → void -
Throws an UnsupportedError;
operations that change the set are disallowed.
inherited
-
retainAll(
Iterable elements) → void -
Throws an UnsupportedError;
operations that change the set are disallowed.
inherited
-
retainWhere(
bool test(E)) → void -
Throws an UnsupportedError;
operations that change the set are disallowed.
inherited
-
retype<
T> () → Set< T> -
Deprecated("Use cast instead")">@Deprecated("Use cast instead")
-
singleWhere(
bool test(E), {E orElse()?}) → E -
Returns the single element that satisfies
test.inherited -
skip(
int n) → Iterable< E> -
Returns an Iterable that provides all but the first
countelements.inherited -
skipWhile(
bool test(E)) → Iterable< E> -
Returns an
Iterablethat skips leading elements whiletestis satisfied.inherited -
take(
int n) → Iterable< E> -
Returns a lazy iterable of the
countfirst elements of this iterable.inherited -
takeWhile(
bool test(E)) → 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 - A string representation of this object.
-
union(
Set< E> other) → Set<E> -
Returns a new set which contains all the elements of this and
other.override -
where(
bool test(E)) → Iterable< E> -
Returns a new lazy Iterable with all elements that satisfy the
predicate
test.inherited -
whereType<
T> () → Iterable< T> -
Returns a new lazy Iterable with all elements that have type
T.inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited