Enum.split_with/3

[virtual-light]

Proposal to expand Enum.split_with/2 with post-process function option similar to how it implemented in Enum.group_by/3 with third argument.

In my experience it is an often case when you need to split a enum through a function with a spec like:

@spec foo(term) :: {:ok, result_t} | {:error, error_t}

and receive two enums, where one contains successful results and another contains errors like: {list(result_t), list(error_t)}.

Enum.map/2 + Enum.split_by/2 seems to be a good choice for this work but unfortunately split_by it doesn't support post-process function (like third argument of Enum.group_by/3 does) so result of applying Enum.split_with/2 will be: {list({:ok, result_t}, list({:error, error_t})} instead.

I propose to expand Enum.split_with to this signature:

@spec split_with(t(), (element() -> as_boolean(term())), (element() -> any())) :: {list(), list()}

split_with(enumerable, split_fun, transform_fun \\ fn x -> x end)

so it can be used like this:

{successful_results, errors} =

  mu_enum

  |> Enum.map(&foo/1)

  |> Enum.split_by(& match?({:ok, _}, &1), fn {_, res} -> res end)

 

Because of lack of transform_fun in current implementation an additional step needed:

{Enum.map(successful_results, fn {_, res} -> res end), Enum.map(errors, fn {_, res} -> res end)}.

[Manish sharma]

Golf Betting Software Development: Everything You Need to Know

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