30秒学会 Dart 片段 – unzip

Creates a list of lists, ungrouping the elements in a list produced by zip.

Use List.generate() twice to generate a list of lists, using the appropriate indexes to get their values from the original list.

代码实现

List<List<T>> unzip<T>(List<List<T>> itr) {
  return List.generate(
      itr[0].length, (i) => List.generate(itr.length, (k) => itr[k][i]));
}

使用样例

unzip([['a', 1, true], ['b', 2, false]]); // [['a', 'b'], [1, 2], [true, false]]
unzip([['a', 1, true], ['b', 2]]); // [['a', 'b'], [1, 2], [true]]