Returns every element that exists in any of the two lists once.

Use the plus operator (+) to concatenate a and b, Iterable.toSet() to get the unique values, Iterable.toList() to return a list.

代码实现

List<T> union<T>(Iterable<T> a, Iterable<T> b) {
  return (a.toList() + b.toList()).toSet().toList();
}

使用样例

union([1, 2, 3], [4, 3, 2]); // [1, 2, 3, 4]