You can do the same in an efficient way with Enum.reduce/3 and prepending to the accumulator:
Enum.reduce(list, [], fn elem, acc -> [fun.(elem) | acc ] end) I think given this is small and straightforward, an addition of reverse_map to the standard library could be something that we can avoid. Andrea On Sun, 31 Mar 2019 at 17:58, Robert Dober <[email protected]> wrote: > Hi there > > I do this all the time, travering a reversed list and accumulating a > transformation into a new list, unreversed now. > > Is this not a very frequent FP pattern. > > I would quite happy to use `Enum.reverse_map` which would be more efficent > than my eternal internal remimplementation: > > ```elixir > > defp map_reverse(collection, fun) > do > > _map_reverse(collection, fun, > []) > > > end > > > > defp _map_reverse(collection, fun, > result) > > defp _map_reverse([], _, result) > do > > > result > > > end > > defp _map_reverse([head|rest], fun, result) > do > > _map_reverse(rest, fun, > [fun.(head)|result]) > > end > ``` > > Any thoughts? > > KR > Robert > > -- > You received this message because you are subscribed to the Google Groups > "elixir-lang-core" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/elixir-lang-core/a4fe903e-9661-448e-ba80-0b8cfc4f8bff%40googlegroups.com > <https://groups.google.com/d/msgid/elixir-lang-core/a4fe903e-9661-448e-ba80-0b8cfc4f8bff%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- Andrea Leopardi [email protected] -- You received this message because you are subscribed to the Google Groups "elixir-lang-core" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/elixir-lang-core/CAM9Rf%2BLpJYUfHg901KY3EF8MwrX3pXHEacrdRywM%3D-qkzw77RQ%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
