An indexable collection of objects with a length.

Subclasses of this class implement different kinds of lists. The most common kinds of lists are:

  • Fixed-length list. An error occurs when attempting to use operations that can change the length of the list.

  • Growable list. Full implementation of the API defined in this class.

The default growable list, as returned by new List() or [], keeps an internal buffer, and grows that buffer when necessary. This guarantees that a sequence of add operations will each execute in amortized constant time. Setting the length directly may take time proportional to the new length, and may change the internal capacity so that a following add operation will need to immediately increase the buffer capacity. Other list implementations may have different performance behavior.

The following code illustrates that some List implementations support only a subset of the API.

List<int> fixedLengthList = new List(5);
fixedLengthList.length = 0;  // Error
fixedLengthList.add(499);    // Error
fixedLengthList[0] = 87;
List<int> growableList = [1, 2];
growableList.length = 0;
growableList.add(499);
growableList[0] = 87;

Lists are Iterable. Iteration occurs over values in index order. Changing the values does not affect iteration, but changing the valid indices—that is, changing the list's length—between iteration steps causes a ConcurrentModificationError. This means that only growable lists can throw ConcurrentModificationError. If the length changes temporarily and is restored before continuing the iteration, the iterator does not detect it.

It is generally not allowed to modify the list's length (adding or removing elements) while an operation on the list is being performed, for example during a call to forEach or sort. Changing the list's length while it is being iterated, either by iterating it directly or through iterating an Iterable that is backed by the list, will break the iteration.

Implements
Implemented by

Properties

first → E
read-only, inherited

Returns the first element.…

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.…

iterator → Iterator<E>
read-only, inherited

Returns a new Iterator that allows iterating the elements of this Iterable.…

last → E
read-only, inherited

Returns the last element.…

length → int
read / write

Returns the number of objects in this list.…

reversed → Iterable<E>
read-only

Returns an Iterable of the objects in this list in reverse order.

single → E
read-only, inherited

Checks that this iterable has only one element, and returns that element.…

Constructors

List([int length])

Creates a list of the given length.…

List.filled(int length, E fill)

Creates a fixed-length list of the given length, and initializes the value at each position with fill:…

List.from(Iterable elements, {bool growable: true})

Creates a list containing all elements.…

List.generate(int length, E generator(int index), {bool growable: true})

Generates a list of values.…

Operators

operator [](int index) → E

Returns the object at the given index in the list or throws a RangeError if index is out of bounds.

operator []=(int index, E value) → void

Sets the value at the given index in the list to value or throws a RangeError if index is out of bounds.

Methods

add(E value) → void

Adds value to the end of this list, extending the length by one.…

addAll(Iterable<E> iterable) → void

Appends all objects of iterable to the end of this list.…

any(bool test(E element)) → bool
inherited

Checks whether any element of this iterable satisfies test.…

asMap() → Map<int,E>

Returns an unmodifiable Map view of this.…

clear() → void

Removes all objects from this list; the length of the list becomes zero.…

contains(Object element) → bool
inherited

Returns true if the collection contains an element equal to element.…

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(Iterable f(E element)) → Iterable
inherited

Expands each element of this Iterableinto zero or more elements.…

fillRange(int start, int end, [E fillValue]) → void

Sets the objects in the range start inclusive to end exclusive to the given fillValue.…

firstWhere(bool test(E element), {E orElse()}) → E
inherited

Returns the first element that satisfies the given predicate test.…

fold(initialValue, dynamic combine(previousValue, E element)) → dynamic
inherited

Reduces a collection to a single value by iteratively combining each element of the collection with an existing value…

forEach(void f(E element)) → void
inherited

Applies the function f to each element of this collection in iteration order.

getRange(int start, int end) → Iterable<E>

Returns an Iterable that iterates over the objects in the range start inclusive to end exclusive.…

indexOf(E element, [int start = 0]) → int

Returns the first index of element in this list.…

insert(int index, E element) → void

Inserts the object at position index in this list.…

insertAll(int index, Iterable<E> iterable) → void

Inserts all objects of iterable at position index in this list.…

join([String separator = ""]) → String
inherited

Converts each element to a String and concatenates the strings.…

lastIndexOf(E element, [int start]) → int

Returns the last index of element in this list.…

lastWhere(bool test(E element), {E orElse()}) → E
inherited

Returns the last element that satisfies the given predicate test.…

map(dynamic f(E element)) → Iterable
inherited

Returns a new lazy Iterable with elements that are created by calling f on each element of this Iterable in iteration order.…

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.…

remove(Object value) → bool

Removes the first occurence of value from this list.…

removeAt(int index) → E

Removes the object at position index from this list.…

removeLast() → E

Pops and returns the last object in this list.…

removeRange(int start, int end) → void

Removes the objects in the range start inclusive to end exclusive.…

removeWhere(bool test(E element)) → void

Removes all objects from this list that satisfy test.…

replaceRange(int start, int end, Iterable<E> replacement) → void

Removes the objects in the range start inclusive to end exclusive and inserts the contents of replacement in its place.…

retainWhere(bool test(E element)) → void

Removes all objects from this list that fail to satisfy test.…

setAll(int index, Iterable<E> iterable) → void

Overwrites objects of this with the objects of iterable, starting at position index in this list.…

setRange(int start, int end, Iterable<E> iterable, [int skipCount = 0]) → void

Copies the objects of iterable, skipping skipCount objects first, into the range start, inclusive, to end, exclusive, of the list.…

shuffle([Random random]) → void

Shuffles the elements of this list randomly.

singleWhere(bool test(E element)) → 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.…

sort([int compare(E a, E b)]) → void

Sorts this list according to the order specified by the compare function.…

sublist(int start, [int end]) → List<E>

Returns a new list containing the objects from start inclusive to end exclusive.…

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.…

toSet() → Set<E>
inherited

Creates a Set containing the same elements as this iterable.…

where(bool test(E element)) → Iterable<E>
inherited

Returns a new lazy Iterable with all elements that satisfy the predicate test.…