shuffle function

void shuffle (List list, [ int start = 0, int end ])

Shuffles a list randomly.

A sub-range of a list can be shuffled by providing start and end.

Implementation 

void shuffle(List list, [int start = 0, int end]) {
  var random = new math.Random();
  if (end == null) end = list.length;
  int length = end - start;
  while (length > 1) {
    int pos = random.nextInt(length);
    length--;
    var tmp1 = list[start + pos];
    list[start + pos] = list[start + length];
    list[start + length] = tmp1;
  }
}