ListQueue class - dart:collection library (original) (raw)
List based Queue.
Keeps a cyclic buffer of elements, and grows to a larger buffer when it fills up. This guarantees constant time peek and remove operations, and amortized constant time add operations.
The structure is efficient for any queue or stack usage.
Example:
final queue = ListQueue<int>();
To add objects to a queue, use add, addAll, addFirst oraddLast.
queue.add(5);
queue.addFirst(0);
queue.addLast(10);
queue.addAll([1, 2, 3]);
print(queue); // {0, 5, 10, 1, 2, 3}
To check if the queue is empty, use isEmpty or isNotEmpty. To find the number of queue entries, use length.
final isEmpty = queue.isEmpty; // false
final queueSize = queue.length; // 6
To get first or last item from queue, use first or last.
final first = queue.first; // 0
final last = queue.last; // 3
To get item value using index, use elementAt.
final itemAt = queue.elementAt(2); // 10
To convert queue to list, call toList.
final numbers = queue.toList();
print(numbers); // [0, 5, 10, 1, 2, 3]
To remove item from queue, call remove, removeFirst or removeLast.
queue.remove(10);
queue.removeFirst();
queue.removeLast();
print(queue); // {5, 1, 2}
To remove multiple elements at the same time, use removeWhere.
queue.removeWhere((element) => element == 1);
print(queue); // {5, 2}
To remove all elements in this queue that do not meet a condition, use retainWhere.
queue.retainWhere((element) => element < 4);
print(queue); // {2}
To remove all items and empty the set, use clear.
queue.clear();
print(queue.isEmpty); // true
print(queue); // {}
Inheritance
Implemented types
Available extensions
Constructors
ListQueue([int? initialCapacity])
Create an empty queue.
ListQueue.from(Iterable elements)
Create a ListQueue containing all elements.
factory
ListQueue.of(Iterable<E> elements)
Create a ListQueue from elements.
factory
Properties
first → E
The first element.
no setter
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 setter
Whether this collection has at least one element.
no setterinherited
A new Iterator that allows iterating the elements of this Iterable.
no setter
last → E
The last element.
no setter
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
Returns the number of elements in the iterable.
no setter
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 setter
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
add(E value)→ void
Adds value at the end of the queue.
override
addAll(Iterable<E> elements)→ void
Adds all elements of iterable at the end of the queue. The length of the queue is extended by the length of iterable.
override
addFirst(E value)→ void
Adds value at the beginning of the queue.
override
addLast(E value)→ void
Adds value at the end of the queue.
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 in the queue. The size of the queue becomes zero.
override
contains(Object? element)→ bool
Whether the collection contains an element equal to element.
inherited
Returns the indexth element.
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 test(E element))→ bool
Checks whether every element of this iterable satisfies test.
inherited
expand<T>(Iterable<T> toElements(E element))→ Iterable<T>
Expands each element of this Iterable into zero or more elements.
inherited
firstWhere(bool test(E element), {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.
join([String separator = ""])→ String
Converts each element to a String and concatenates the strings.
inherited
lastWhere(bool test(E element), {E orElse()?})→ E
The last element that satisfies the given predicate test.
inherited
map<T>(T toElement(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 a single instance of value from the queue.
override
removeFirst()→ E
Removes and returns the first element of this queue.
override
removeLast()→ E
Removes and returns the last element of the queue.
override
removeWhere(bool test(E element))→ void
Remove all elements matched by test.
override
retainWhere(bool test(E element))→ void
Remove all elements not matched by test.
override
singleWhere(bool test(E element), {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 element))→ 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 element))→ 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.
Creates a Set containing the same elements as this iterable.
inherited
Returns a string representation of (some of) the elements of this.
override
where(bool test(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