 
       iex> Enum.slice([1, 2, 3, 4, 5], 0..-1//2)
       [1, 3, 5]
+
+  To get every third element of the first ten elements:
+
+      iex> integers = Enum.to_list(1..20)
+      iex> Enum.slice(integers, 0..9//3)
+      [1, 4, 7, 10]
 
   If the first position is after the end of the enumerable
   or after the last position of the range, it returns an

      iex> Enum.slice([1, 2, 3, 4, 5], 3..10)
      [4, 5]

      # last three elements (negative indexes)
      iex> Enum.slice([1, 2, 3, 4, 5], -3..-1)
      [3, 4, 5]


  `enumerable`, or this one is greater than the normalized `index_range.last`,
  then `[]` is returned.

  If a step `n` (other than `1`) is used in `index_range`, then it takes
  every `n`th element from `index_range.first` to `index_range.last`
  (according to the same rules described above).

  ## Examples

      iex> Enum.slice([1, 2, 3, 4, 5], 1..3)
