Filters out the unique values in a list.

Use Iterable.where() in combination with List.indexOf() and List.lastIndexOf() to filter out the unique values.

代码实现

List<T> filterUnique<T>(List<T> lst) {
  return lst.where((i) => lst.indexOf(i) != lst.lastIndexOf(i)).toList();
}

使用样例

filterUnique([1, 2, 2, 3, 4, 4, 5]); // [2, 2, 4, 4]