List<E> class

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 created by [], 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.

Implementers

Constructors

List([int length])
Creates a list of the given length. [...]
factory
List.empty({bool growable: false})
Creates a new empty list. [...]
factory
List.filled(int length, E fill, {bool growable: false})
Creates a list of the given length with fill at each position. [...]
factory
List.from(Iterable elements, {bool growable: true})
Creates a list containing all elements. [...]
factory
List.generate(int length, E generator(int index), {bool growable: true})
Generates a list of values. [...]
factory
List.of(Iterable<E> elements, {bool growable: true})
Creates a list from elements. [...]
factory
List.unmodifiable(Iterable elements)
Creates an unmodifiable list containing all elements. [...]
factory

Properties

first ↔ E
Returns the first element. [...]
read / write, inherited-getter
hashCode int
The 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>
Returns a new Iterator that allows iterating the elements of this Iterable. [...]
read-only, inherited
last ↔ E
Returns the last element. [...]
read / write, inherited-getter
length int
The number of objects in this list. [...]
read / write
reversed Iterable<E>
Returns an Iterable of the objects in this list in reverse order.
read-only
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

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
Checks whether any element of this iterable satisfies test. [...]
inherited
asMap() Map<int, E>
Returns an unmodifiable Map view of this. [...]
cast<R>() List<R>
Returns a view of this list as a list of R instances. [...]
override
clear() → void
Removes all objects from this list; the length of the list becomes zero. [...]
contains(Object element) bool
Returns true if the collection contains an element equal to element. [...]
inherited
elementAt(int index) → E
Returns the indexth element. [...]
inherited
every(bool test(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
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
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 concatentation of this iterable and other. [...]
inherited
forEach(void f(E element)) → void
Applies the function f to each element of this collection in iteration order.
inherited
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. [...]
indexWhere(bool test(E element), [int start = 0]) int
Returns the first index in the list that satisfies the provided test. [...]
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
Converts each element to a String and concatenates the strings. [...]
inherited
lastIndexOf(E element, [int start]) int
Returns the last index of element in this list. [...]
lastIndexWhere(bool test(E element), [int start]) int
Returns the last index in the list that satisfies the provided test. [...]
lastWhere(bool test(E element), {E orElse()}) → E
Returns the last element that satisfies the given predicate test. [...]
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 this Iterable 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 the first occurrence 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 orElse()}) → 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 while test is satisfied. [...]
inherited
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 elements between start and end. [...]
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
where(bool test(E element)) 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 +(List<E> other) List<E>
Returns the concatenation of this list and other. [...]
operator ==(Object other) bool
Whether this list is equal to other. [...]
override
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.

Static Methods

castFrom<S, T>(List<S> source) List<T>
Adapts source to be a List<T>. [...]
override
copyRange<T>(List<T> target, int at, List<T> source, [int start, int end]) → void
Copy a range of one list into another list. [...]
writeIterable<T>(List<T> target, int at, Iterable<T> source) → void
Write the elements of an iterable into a list. [...]