How can i split a binary in erlang

Question

What I want is, I think, relatively simple:

> Bin = <<\"Hello.world.howdy?\">>.
> split(Bin, \".\").
[<<\"Hello\">>, <<\"         


        

Answer 1

There is no current OTP function that is the equivalent of lists:split/2 that works on a binary string. Until EEP-9 is made public, you might write a binary split function like:

split(Binary, Chars) ->
    split(Binary, Chars, 0, 0, []).

split(Bin, Chars, Idx, LastSplit, Acc)
  when is_integer(Idx), is_integer(LastSplit) ->
    Len = (Idx - LastSplit),
    case Bin of
        <<_:LastSplit/binary,
         This:Len/binary,
         Char,
         _/binary>> ->
            case lists:member(Char, Chars) of
                false ->
                    split(Bin, Chars, Idx+1, LastSplit, Acc);
                true ->
                    split(Bin, Chars, Idx+1, Idx+1, [This | Acc])
            end;
        <<_:LastSplit/binary,
         This:Len/binary>> ->
            lists:reverse([This | Acc]);
        _ ->
            lists:reverse(Acc)
    end.