getRange method

@override Iterable<T> getRange(int start, int end)

Creates an Iterable that iterates over a range of elements.

The returned iterable iterates over the elements of this list with positions greater than or equal to start and less than end.

The provided range, start and end, must be valid at the time of the call. A range from start to end is valid if 0 ≤ start ≤ end ≤ length. An empty range (with end == start) is valid.

The returned Iterable behaves like skip(start).take(end - start). That is, it does not break if this list changes size, it just ends early if it reaches the end of the list early (if end, or even start, becomes greater than length).

final colors = <String>['red', 'green', 'blue', 'orange', 'pink'];
final firstRange = colors.getRange(0, 3);
print(firstRange.join(', ')); // red, green, blue

final secondRange = colors.getRange(2, 5);
print(secondRange.join(', ')); // blue, orange, pink

Implementation

@override
Iterable<T> getRange(int start, int end) sync* {
  final startStart = _start;
  final startEnd = _end;
  final (normalizedStart, normalizedEnd) =
      _validateAndNormalizeRange(start, end);
  for (int i = normalizedStart; i < normalizedEnd; i++) {
    yield _list[i];
    if (_start != startStart || _end != startEnd) {
      throw ConcurrentModificationError(
          "This slice was modified while yielding entries.");
    }
  }
}