You also can use flat_map
iex> [ ...> [[1, 2, 3], [4, 5, 6]], ...> [[1, 2, 3], [4, 5, 6]] ...> ] |> Enum.flat_map(fn x -> x end) [[1, 2, 3], [4, 5, 6], [1, 2, 3], [4, 5, 6]]