How to convert charlist to string?

Hello. I’m working on running python file by elixir.
The python file returns dict, and elixir parses it as map. But its keys are charlists like this:

%{'graph' => {:"$erlport.opaque", :python, <<128, 2, 99, 110, 101, 111, 52, 106, 46, 103, 114, 97, 112, 104, 10, 71, 114, 97, 112, 104, 10, 113, 0, 41, 129, 113, 1, 125, 113, 2, 40, 88, 6, 0, 0, 0, 95, 110, 111, 100, 101, 115, 113, 3, 125, 113, ...>>}, 'id' => 7, 'labels' => ...

I have never seen a map which has charlist keys, so I’d like to convert the key to string, but I don’t still find a good way to do it. Do you have an idea for it? Thank you :smile:

What library do use for interactions with Python? I think it might have an option to return binaries instead of charlists

But until then you can just charlist = 'abc'; string = "#{charlist}" or use to_string. To traverse maps, you can use Map.new()

So, to convert one map, you should write something like

Map.new(old_map, fn
  {list, value} when is_list(list) ->
    key =
      try do
        "#{list}"
      except
        # In case it's not a charlist
        _ -> list
      end

    {key, value}

  other ->
    other
end)
2 Likes

Post removed. @hissssst was faster :slight_smile:

1 Like

Thank you! I converted it to string by to_string()!

This code is pretty defensive. I’d probably do:

 Map.new(map, fn {k, v} -> {List.to_string(k), v} end)

And let List.to_string/1 handle the edge-cases.

3 Likes

Oh, I’ve just found out that Python can’t have lists as dict keys by default. But there can still be tweaks, so extra handling is never killed anyone

The “Let is crash” philosophy is supposed to keep us from (premature) defensive code, as less code has advantages (less code, less bugs etc).

I would say the shorter code of @adamu is better in this case.

Can you tell us what you’ve used?

erlport but it was a long time ago and I can’t remember anything about the library today