Elixir example: Anagram counter

anagram-counter.ex

defmodule Anagrams do
  def anagram_counter(words, n) do
    words
    |> Enum.filter(fn word -> String.length(word) == n end)
    |> Enum.reduce(%{}, fn word, lookup ->
      Map.update(lookup, lookup_key(word), MapSet.new([word]), &MapSet.put(&1, word))
    end)
    |> Enum.count(fn {_key, anagram_words} -> MapSet.size(anagram_words) > 1 end)
  end

  defp lookup_key(word),
    do: word |> String.downcase() |> String.graphemes() |> Enum.sort() |> Enum.join()
end