Help to simplify/optimize a function

Questions & Help Questions
,
16

Naive solution on a first try:

defmodule IntMapSanitizer do
  @test_map_1 %{
    greet: "Hirrow",
    int_a: "17",
    int_b: "gibberish",
    int_c: "428",
    farewell: "Aufwiedersehen"
  }

  defp is_int_name?(k) when is_atom(k) do
    k
    |> Atom.to_string()
    |> String.starts_with?("int_")
  end

  defp should_keep?(v) when is_nil(v) or is_integer(v), do: false
  defp should_keep?(_), do: true

  defp parse_to_int_or_nil(v) do
    case Integer.parse(v) do
      :error ->
        nil

      {parsed, _} ->
        parsed
    end
  end

  def sanitize(%{} = map) do
    for {k, v} <- map, is_int_name?(k), should_keep?(v), reduce: map do
      acc -> Map.update(acc, k, nil, &parse_to_int_or_nil(&1))
    end
  end

  def test1() do
    sanitize(@test_map_1)
  end
end

Try in iex:

iex(1)> IntMapSanitizer.test1()
%{
  farewell: "Aufwiedersehen",
  greet: "Hirrow",
  int_a: 17,
  int_b: nil,
  int_c: 428
}

Haven’t measured but for comprehensions with filters and the reduce option have always been fairly fast in my experience.

Maybe if you make a public GitHub repo then we can make a benchmarking arena. :slight_smile: