SplayTreeSet class - dart:collection library (original) (raw)
SplayTreeSet<E> class final
A Set of objects that can be ordered relative to each other.
The set is based on a self-balancing binary tree. It allows most operations in amortized logarithmic time.
Elements of the set are compared using the compare function passed in the constructor, both for ordering and for equality. If the set contains only an object a, then set.contains(b)will return true if and only if compare(a, b) == 0, and the value of a == b is not even checked. If the compare function is omitted, the objects are assumed to beComparable, and are compared using their Comparable.compareTo method. Non-comparable objects (including null) will not work as an element in that case.
**Note:**Do not modify a set (add or remove elements) while an operation is being performed on that set, for example in functions called during a forEach or containsAll call, or while iterating the set.
Do not modify elements in a way which changes their equality (and thus their hash code) while they are in the set. Some specialized kinds of sets may be more permissive with regards to equality, in which case they should document their different behavior and restrictions.
Example:
final planets = SplayTreeSet<String>((a, b) => a.compareTo(b));
To add data to a set, use add or addAll.
planets.add('Neptune');
planets.addAll({'Venus', 'Mars', 'Earth', 'Jupiter'});
print(planets); // {Earth, Jupiter, Mars, Neptune, Venus}
To check if the set is empty, use isEmpty or isNotEmpty. To find the number of elements in the set, use length.
final isEmpty = planets.isEmpty; // false
final length = planets.length; // 5
To check whether the set contains a specific element, use contains.
final marsExists = planets.contains('Mars'); // true
To get element value using index, use elementAt.
final elementAt = planets.elementAt(1);
print(elementAt); // Jupiter
To make a copy of set, use toSet.
final copySet = planets.toSet(); // a `SplayTreeSet` with the same ordering.
print(copySet); // {Earth, Jupiter, Mars, Neptune, Venus}
To remove an element, use remove.
final removedValue = planets.remove('Mars'); // true
print(planets); // {Earth, Jupiter, Neptune, Venus}
To remove multiple elements at the same time, use removeWhere.
planets.removeWhere((element) => element.startsWith('J'));
print(planets); // {Earth, Neptune, Venus}
To removes all elements in this set that do not meet a condition, use retainWhere.
planets.retainWhere((element) => element.contains('Earth'));
print(planets); // {Earth}
To remove all elements and empty the set, use clear.
planets.clear();
print(planets.isEmpty); // true
print(planets); // {}
See also:
- Set is a base-class for collection of objects.
- HashSet the order of the objects in the iterations is not guaranteed.
- LinkedHashSet objects stored based on insertion order.
Mixed-in types
Available extensions
Constructors
SplayTreeSet([int compare(E key1, E key2)?, bool isValidKey(dynamic potentialKey)?])
Create a new SplayTreeSet with the given compare function.
SplayTreeSet.from(Iterable elements, [int compare(E key1, E key2)?, bool isValidKey(dynamic potentialKey)?])
Creates a SplayTreeSet that contains all elements.
factory
SplayTreeSet.of(Iterable<E> elements, [int compare(E key1, E key2)?, bool isValidKey(dynamic potentialKey)?])
Creates a SplayTreeSet from elements.
factory
Properties
first → E
The first element.
no setteroverride
firstOrNull → T?
Available on Iterable<T>, provided by the IterableExtensions extension
The first element of this iterator, or null if the iterable is empty.
no setter
The hash code for this object.
no setterinherited
Available on Iterable<T>, provided by the IterableExtensions extension
Pairs of elements of the indices and elements of this iterable.
no setter
Whether this collection has no elements.
no setteroverride
Whether this collection has at least one element.
no setteroverride
A new Iterator that allows iterating the elements of this Iterable.
no setteroverride
last → E
The last element.
no setteroverride
lastOrNull → T?
Available on Iterable<T>, provided by the IterableExtensions extension
The last element of this iterable, or null if the iterable is empty.
no setter
The number of elements in this Iterable.
no setteroverride
Available on Iterable<T?>, provided by the NullableIterableExtensions extension
The non-null elements of this iterable.
no setter
A representation of the runtime type of the object.
no setterinherited
single → E
Checks that this iterable has only one element, and returns that element.
no setteroverride
singleOrNull → T?
Available on Iterable<T>, provided by the IterableExtensions extension
The single element of this iterator, or null.
no setter
Available on Iterable<Future<T>>, provided by the FutureIterable extension
Waits for futures in parallel.
no setter
Methods
Adds value to the set.
override
addAll(Iterable<E> elements)→ void
Adds all elements to this set.
override
any(bool test(E element))→ bool
Checks whether any element of this iterable satisfies test.
inherited
Available on Iterable<T>, provided by the EnumByName extension
Creates a map from the names of enum values to the values.
Available on Iterable<T>, provided by the EnumByName extension
Finds the enum value in this list with name name.
A view of this iterable as an iterable of R instances.
override
clear()→ void
Removes all elements from the set.
override
contains(Object? element)→ bool
Whether the collection contains an element equal to element.
override
containsAll(Iterable<Object?> other)→ bool
Whether this set contains all the elements of other.
inherited
difference(Set<Object?> other)→ Set<E>
Creates a new set with the elements of this that are not in other.
override
Returns the indexth element.
inherited
elementAtOrNull(int index)→ T?
Available on Iterable<T>, provided by the IterableExtensions extension
The element at position index of this iterable, or null.
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 value), {E orElse()?})→ E
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>
Creates the lazy concatenation of this iterable and other.
inherited
forEach(void f(E element))→ void
Invokes action on each element of this iterable in iteration order.
inherited
intersection(Set<Object?> other)→ Set<E>
Creates a new set which is the intersection between this set and other.
override
join([String separator = ""])→ String
Converts each element to a String and concatenates the strings.
inherited
lastWhere(bool test(E value), {E orElse()?})→ E
The last element that satisfies the given predicate test.
inherited
If an object equal to object is in the set, return it.
override
map<T>(T f(E element))→ Iterable<T>
The current elements of this iterable modified by toElement.
inherited
noSuchMethod(Invocation invocation)→ dynamic
Invoked when a nonexistent 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
Removes value from the set.
override
removeAll(Iterable<Object?> elements)→ void
Removes each element of elements from this set.
override
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.
override
retainWhere(bool test(E element))→ void
Removes all elements of this set that fail to satisfy test.
inherited
singleWhere(bool test(E value), {E orElse()?})→ E
The single element that satisfies test.
inherited
Creates an Iterable that provides all but the first count elements.
inherited
skipWhile(bool test(E value))→ Iterable<E>
Creates an Iterable that skips leading elements while test is satisfied.
inherited
Creates a lazy iterable of the count first elements of this iterable.
inherited
takeWhile(bool test(E value))→ Iterable<E>
Creates 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
Creates a Set containing the same elements as this iterable.
override
A string representation of this object.
override
Creates a new set which contains all the elements of this set and other.
override
where(bool f(E element))→ Iterable<E>
Creates a new lazy Iterable with all elements that satisfy the predicate test.
inherited
Creates a new lazy Iterable with all elements that have type T.
inherited
Operators
operator ==(Object other)→ bool
The equality operator.
inherited