strings.ex

defmodule Strings do
  #   def remove_chars!(str, _chars) do
  #     String.replace(str, ~r([\-\+\/\*]), "")
  #   end

  def remove_chars(str, chars) do
    source = String.split(str, "")
    chars = String.split(chars, "")

    Enum.reduce(source, [], fn ch, acc ->
      if ch not in chars do
        acc ++ [ch]
      else
        acc
      end
    end)
    |> Enum.join()
  end

  def split_even_and_odd(numbers) do
    Enum.reduce(numbers, %{odd: [], even: []}, fn n, splitted ->
      if rem(n, 2) == 0 do
        %{splitted | even: splitted[:even] ++ [n]}
      else
        %{splitted | odd: splitted[:odd] ++ [n]}
      end
    end)
  end

  def collect_odd_numbers(numbers) do
    Enum.reduce(numbers, [], fn n, odds ->
      if rem(n, 2) == 0, do: odds, else: odds ++ [n]
    end)
  end
end