length property
The number of objects in this list.
The valid indices for a list are 0 through length - 1.
final numbers = <int>[1, 2, 3];
print(numbers.length); // 3
Implementation
@override
int get length => _length;Setting the length changes the number of elements in the list.
The list must be growable.
If newLength is greater than current length,
new entries are initialized to null,
so newLength must not be greater than the current length
if the element type E is non-nullable.
final maybeNumbers = <int?>[1, null, 3];
maybeNumbers.length = 5;
print(maybeNumbers); // [1, null, 3, null, null]
maybeNumbers.length = 2;
print(maybeNumbers); // [1, null]
final numbers = <int>[1, 2, 3];
numbers.length = 1;
print(numbers); // [1]
numbers.length = 5; // Throws, cannot add `null`s.
Implementation
@override
set length(int newLength) {
if (newLength < 0) {
throw RangeError.range(newLength, 0, _length, 'newLength');
}
if (newLength == _length) return;
if (newLength < _length) {
// Truncate the list
while (_length > newLength) {
removeLast();
}
} else {
// Extend the list with nulls (if E is nullable) or default values
if (null is! E) {
throw UnsupportedError(
'Cannot extend a LinkedList with non-nullable elements without a default value.');
}
while (_length < newLength) {
add(null as E); // Add nulls for nullable types
}
}
}