30秒学会 Dart 片段 – bifurcateBy

Splits values into two groups according to a predicate function, which specifies which group an element in the input collection belongs to.
If the predicate function returns true, the collection element belongs to the first group; otherwise, it belongs to the second group.

Use Iterable.retainWhere() and Iterable.removeWhere() in combination with the cascade operator (..) and List.from() to create the appropriate groups using the filter function.

代码实现

List<List<T>> bifurcateBy<T>(List<T> lst, bool Function(T) filter) {
  return [
    List.from(lst..retainWhere(filter)),
    List.from(lst..removeWhere(filter))
  ];
}

使用样例

bifurcateBy(['beep', 'boop', 'foo', 'bar'], (x) => x[0] == 'b'); // [['beep', 'boop', 'bar'], ['foo']]