intersperse

Insert an element between each element of an Iterable or List.

    final list1 = intersperse(2, <int>[]); // [];
    final list2 = intersperse(2, [0]); // [0];
    final list3 = intersperse(2, [0, 0]); // [0, 2, 0];
    final list1Outer = intersperseOuter(2, <int>[]); // [];
    final list2Outer = intersperseOuter(2, [0]); // [2, 0, 2];
    final list3Outer = intersperseOuter(2, [0, 0]); // [2, 0, 2, 0, 2];

This can also be used as an extension method:

    final list1 = <int>[].intersperse(2); // [];
    final list2 = [0].intersperse(2); // [0];
    final list3 = [0, 0].intersperse(2); // [0, 2, 0];
    final list1Outer = <int>[].intersperseOuter(2); // [];
    final list2Outer = [0].intersperseOuter(2); // [2, 0, 2];
    final list3Outer = [0, 0].intersperseOuter(2); // [2, 0, 2, 0, 2];