import 'dart:math';

Random rng = new Random();

/// Swap given [index1] and [index2] in given [collection]
void swap<T>(List<T> collection, int index1, int index2) {
  T temp = collection[index1];
  collection[index1] = collection[index2];
  collection[index2] = temp;
}

/// Randomly shuffle given [collection] (inplace)
void shuffle<T>(List<T> collection) {
  for (int i = collection.length - 1; i > 1; i--) {
    swap(collection, i, rng.nextInt(i - 1));
  }
}

main() {
  List<double> someList = [1, 2, 3, 4, 5];
  print(someList);
  shuffle(someList);
  print(someList);
  shuffle(someList);
  print(someList);
  shuffle(someList);
  print(someList);
}