List<E> constructor Null safety
- [int? length]
Creates a list of the given length.
NOTICE: This constructor cannot be used in null-safe code.
Use List.filled to create a non-empty list.
This requires a fill value to initialize the list elements with.
To create an empty list, use []
for a growable list or
List.empty
for a fixed length list (or where growability is determined
at run-time).
The created list is fixed-length if length
is provided.
List fixedLengthList = new List.filled(3);
fixedLengthList.length; // 3
fixedLengthList.length = 1; // Error
The list has length 0 and is growable if length
is omitted.
List growableList = [];
growableList.length; // 0;
growableList.length = 3;
To create a growable list with a given length, for a nullable element type, just assign the length right after creation:
List growableList = []..length = 500;
For a non-nullable element type, an alternative is the following:
List<int> growableList = List<int>.filled(500, 0, growable: true);
The length
must not be negative or null, if it is provided.
If the element type is not nullable, length
must not be greater than
zero.
Implementation
@deprecated
external factory List([int? length]);