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

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

List<int> list1 = [1, 2, 3, 4];
List<int> list2 = [5, 6, 7, 8, 9];
// Copies the 4th and 5th items in list2 as the 2nd and 3rd items
// of list1.
list1.setRange(1, 3, list2, 3);
list1.join(', '); // '1, 8, 9, 4'

The start and end indices must satisfy 0 ≤ start ≤ end ≤ length. If start equals end, this method has no effect.

The iterable must have enough objects to fill the range from start to end after skipping skipCount objects.

If iterable is this list, the operation will copy the elements originally in the range from skipCount to skipCount + (end - start) to the range start to end, even if the two ranges overlap.

If iterable depends on this list in some other way, no guarantees are made.

Source 

void setRange(int start, int end, Iterable<E> iterable, [int skipCount = 0]) {
  RangeError.checkValidRange(start, end, this.length);
  int length = end - start;
  if (length == 0) return;
  RangeError.checkNotNegative(skipCount, "skipCount");

  List<E> otherList;
  int otherStart;
  // TODO(floitsch): Make this accept more.
  if (iterable is List/*<E>*/) {
    otherList = iterable;
    otherStart = skipCount;
  } else {
    otherList = iterable.skip(skipCount).toList(growable: false);
    otherStart = 0;
  }
  if (otherStart + length > otherList.length) {
    throw IterableElementError.tooFew();
  }
  if (otherStart < start) {
    // Copy backwards to ensure correct copy if [from] is this.
    for (int i = length - 1; i >= 0; i--) {
      this[start + i] = otherList[otherStart + i];
    }
  } else {
    for (int i = 0; i < length; i++) {
      this[start + i] = otherList[otherStart + i];
    }
  }
}