Returns true if two lists contain the same elements regardless of order, false otherwise.

Use the plus operator (+) to concatenate a and b, Iterable.toSet() to get all the unique values.
Use a for..in loop and compare the occurence count of each value between the two lists.
Return false if any occurence count doesn’t match, true otherwise.

代码实现

bool haveSameContents<T>(List<T> a, List<T> b) {
  for (T v in (a + b).toSet())
    if (a.where((e) => e == v).length != b.where((e) => e == v).length)
      return false;
  return true;
}

使用样例

haveSameContents([1, 2, 4], [2, 4, 1]); // true