Not for lists it doesn't https://github.com/elixir-lang/elixir/blob/cbe03987daa9c01a9d7ce99137a1d76535efb5f9/lib/elixir/lib/enum.ex#L1185
Enum.map is for all intents and purposes exactly as fast as :lists.map. :maps.fold just converts a map to a list and folds over it, and then turns it back into a map. On Thursday, July 7, 2016 at 6:25:28 PM UTC-4, Peter Hamilton wrote: > > To be fair, :maps.map is the fastest. But it's about as fast as :lists.map > . Enum has a lot of overhead. > > On Thu, Jul 7, 2016 at 3:23 PM Ben Wilson <[email protected] > <javascript:>> wrote: > >> This is correct. map |> Enum.map(&fun) |> Map.new is the fastest possible >> way to take a map and iterate over all of its keys. >> >> Reason being, building a new list of {k, v} pairs and calling the >> `:maps.from_list` NIF always beats out N Map.put calls, which is how into: >> %{} works. It also creates less garbage. Map.new is basically just >> :maps.from_list if it gets passed a list. >> >> >> On Thursday, July 7, 2016 at 2:48:39 PM UTC-4, Michał Muskała wrote: >> >>> What do you mean by not converting to a list? >>> The fastest way right now of doing a map on a map is actually to convert >>> to list, map and convert back to a map. >>> I’d suspect that’s the case with a lot of data structures as well, >>> actually. Lists are simply really good for recursion. >>> The benefit is even greater if you do multiple operations on those >>> lists, as the conversion happens (ideally) only >>> once. >>> >>> Michał. >>> >>> On 07 Jul 2016, at 19:35, Peter Hamilton <[email protected]> wrote: >>> >>> Does the Enumerable protocol enable the performance improvement of not >>> converting to a list? I don't think it does. >>> >>> On Thu, Jul 7, 2016, 10:24 AM Andrea Leopardi <[email protected]> >>> wrote: >>> >>> Enum.into/3 should do what you want :) >>>> >>>> On Thursday, 7 July 2016, Wiebe-Marten Wijnja <[email protected]> >>>> wrote: >>>> >>>>> I propose to add `into: collectable` as optional third argument to >>>>> Enum.map. >>>>> >>>>> This would allow mapping over things without first converting it to a >>>>> list and then convert it back. >>>>> >>>>> So: >>>>> >>>>> %{"a" => 1, "b" => 2} >>>>> |> Enum.map(fn {k, v} -> {String.upcase(k), v} end) >>>>> |> Enum.into(%{}) >>>>> >>>>> could be written as: >>>>> >>>>> %{"a" => 1, "b" => 2} >>>>> |> Enum.map(fn {k, v} -> {String.upcase(k), v} end, into: %{}) >>>>> >>>>> Not having to do the list conversion in the middle might also improve >>>>> performance. >>>>> >>>>> >>>>> Right now, enumerating and collecting in one go is of course possible >>>>> using `Kernel.SpecialForms.for`. `for` is however not very >>>>> pipeline-friendly. >>>>> >>>>> >>>>> What do you think? >>>>> >>>>> >>>>> Sincerely, >>>>> >>>>> ~Wiebe-Marten >>>>> >>>>> -- >>>>> 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/23c345b9-9ba1-48ea-8db0-6d2e9e700473%40googlegroups.com >>>>> >>>>> <https://groups.google.com/d/msgid/elixir-lang-core/23c345b9-9ba1-48ea-8db0-6d2e9e700473%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%2BLY6tyh%3DE6iM%2BA7rmyY8dKP-ddCJpB%2BWZDn0jCuJ7FKaA%40mail.gmail.com >>>> >>>> <https://groups.google.com/d/msgid/elixir-lang-core/CAM9Rf%2BLY6tyh%3DE6iM%2BA7rmyY8dKP-ddCJpB%2BWZDn0jCuJ7FKaA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>> . >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> >>> -- >>> 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/CAOMhEnyR_50BhVdVugiQqDUxY9jUBNRCR23Bao%3DhwQ9Zmeh4PA%40mail.gmail.com >>> >>> <https://groups.google.com/d/msgid/elixir-lang-core/CAOMhEnyR_50BhVdVugiQqDUxY9jUBNRCR23Bao%3DhwQ9Zmeh4PA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >>> For more options, visit https://groups.google.com/d/optout. >>> >>> -- >> 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] <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/elixir-lang-core/af052020-b329-49e0-a7b7-f0bf487c123c%40googlegroups.com >> >> <https://groups.google.com/d/msgid/elixir-lang-core/af052020-b329-49e0-a7b7-f0bf487c123c%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> > -- You received this message because you are subscribed to the Google Groups "elixir-lang-core" group. 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