Fizzbuzz in Elixir

fizzbuzz.markdown

Fizzbuzz in Elixir

Elixir is a beautiful language. Among its strength is its powerful pattern matching system which allows one to write very declarative, elegant code. FizzBuzz is a trivial problem often presented to new programmers or interviewees to determine baseline programming ability. Here is a solution Elixir:

defmodule FizzBuzz do
  def fizz do
    (1..100)
    |> Enum.map(&buzz/1)
    |> Enum.each(&IO.puts/1)
  end

  defp buzz(i) when rem(i, 15) == 0, do: "FizzBuzz"
  defp buzz(i) when rem(i, 5)  == 0, do: "Buzz"
  defp buzz(i) when rem(i, 3)  == 0, do: "Fizz"
  defp buzz(i),                      do: Integer.to_string(i)
end

This kind of declarative syntax frequently makes handling changes in business requirements as easy as adding an additional definition for a function.

defmodule FizzBuzz do
  def build_list(range, types),
    do: Enum.map(range, &entry(&1, types))

  defp entry(n, types) do
    for {d, val} <- types,
        rem(n, d) == 0,
        reduce: n do
      acc when is_integer(acc) -> val
      acc -> [acc, val]
    end
    |> to_string()
  end
end

types = [
  {3, "Fizz"},
  {5, "Buzz"}
]

1..100
|> FizzBuzz.build_list(types)
|> Enum.intersperse(?\n)
|> IO.puts()