DOCUMENTATION:
  name: zip_longest
  version_added: "2.3"
  short_description: combine list elements, with filler
  positional: _input, _additional_lists
  description:
      - Make an iterator that aggregates elements from each of the iterables.
        If the iterables are of uneven length, missing values are filled-in with I(fillvalue).
        Iteration continues until the longest iterable is exhausted.
  notes:
    - This is mostly a passhtrough to Python's C(itertools.zip_longest) function
  options:
    _input:
      description: Original list.
      type: list
      elements: any
      required: yes
    _additional_lists:
      description: Additional list(s).
      type: list
      elements: any
      required: yes
    fillvalue:
      description: Filler value to add to output when one of the lists does not contain enough elements to match the others.
      type: any

EXAMPLES: |

    # X_fill => [[1, "a", 21], [2, "b", 22], [3, "c", 23], ["X", "d", "X"], ["X", "e", "X"], ["X", "f", "X"]]
    X_fill: "{{ [1,2,3] | zip_longest(['a','b','c','d','e','f'], [21, 22, 23], fillvalue='X') }}"

RETURN:
  _value:
    description: List of lists made of elements matching the positions of the input lists.
    type: list
    elements: list