How can I get permutations of a list?

Question

How can I get permutations of a list in Elixir?

Eg, for ["a", "b", "c"], I would expect:

# [["a", "b", "c"], ["a", "c", "b"], 
# ["b", "a", "c"], ["b", "c", "a"],
# ["c", "a", "b"], ["c", "b", "a"]]

Answer 1

Like this:

defmodule Permutations do
  def of([]) do
    [[]]
  end

  def of(list) do
    for h <- list, t <- of(list -- [h]), do: [h | t]
  end
end