A small benchmark comparing different implementations of a possible pop_by functionality

pop_by benchmark.exs

# Keyboard mashing
tags = ~w(faoshd foasidf oasidfh oaidsf aosifhasodi faosdfaosdfasodfjasldfd noasdfn 1234234 oasdinf oasnfoasdifnoisdfnof)

defmodule Popper do
  def pop_by(list, fun, default \\ nil) do
    result = Enum.find(list, default, fun)

    {result, List.delete(list, result)}
  end

  def pop_by2(list, fun, default \\ nil) do
    case Enum.split_with(list, fun) do
      {[result], other} -> {result, other}
      {[], other} -> {default, other}
    end
  end

  def pop_by3(list, fun, default \\ nil) do
    {result, others} =
      :lists.foldr(fn
        tag, {nil, acc} ->
          if fun.(tag) do
            {tag, acc}
          else
            {nil, [tag | acc]}
          end
        tag, {found, acc} ->
          {found, [tag | acc]}
      end, {nil, []}, list)

    {result || default, others}
  end

  def integer_string?(str) do
    match?({i, _} when is_integer(i), Integer.parse(str))
  end
end

# Save some writing
# Tries to find a string that can be parsed from a list and return 720 by default
simple_fun = fn fun ->
  fn -> fun.(tags, &Popper.integer_string?/1, 720) end
end

Benchee.run(
  %{
    "find & delete" => simple_fun.(&Popper.pop_by/3),
    "split_with" => simple_fun.(&Popper.pop_by2/3),
    "foldr" => simple_fun.(&Popper.pop_by3/3)
  },
  time: 10,
  memory_time: 2
)