It would be nice to have this. On Sun, Aug 18, 2019 at 5:16 PM Roman Smirnov <pom...@gmail.com> wrote:
> > My bad, I was referring to Enum.reject/2! > > Well, Map.reject/2 does not exist yet. So, we could add it as well. > > понедельник, 19 августа 2019 г., 0:35:41 UTC+3 пользователь Andrea > Leopardi написал: >> >> > Why? How Enum.drop/2 is related to Enum.filter/2? They are doing >> completely different things. >> >> My bad, I was referring to Enum.reject/2! >> >> Andrea Leopardi >> an.le...@gmail.com >> >> >> On Sat, Aug 17, 2019 at 11:42 PM Roman Smirnov <pom...@gmail.com> wrote: >> >>> Why? How Enum.drop/2 is related to Enum.filter/2? They are doing >>> completely different things. >>> >>> четверг, 15 августа 2019 г., 13:37:07 UTC+3 пользователь Andrea Leopardi >>> написал: >>>> >>>> We should also address the fact that if we add Map.filter/2, we also >>>> likely have to add Map.drop/2 (to mimic Enum and Stream), but that name is >>>> already taken. >>>> >>>> On Thu, 15 Aug 2019 at 12:26, Johanna Larsson <johanna....@gmail.com> >>>> wrote: >>>> >>>>> The stream version is by far the slowest, which isn't surprising since >>>>> streams bring some overhead. Didn't measure memory usage though >>>>> https://gist.github.com/joladev/2b51260107078a1fc7f9d4504916fe21 >>>>> >>>>> Honestly, I tend to agree it would be nice to add it, for feature >>>>> completeness, even if it doesn't improve performance hugely. I understand >>>>> the desire to avoid unnecessary clutter in the core language, but this is >>>>> a >>>>> core erlang function that we're explicitly not wrapping, when most of the >>>>> other ones are wrapped. And most likely just because it wasn't around from >>>>> the start. It's quite a bit more ergonomic to use `Map.filter` rather than >>>>> `for` or `map|>Enum.filter(pred)|>Enum.into({})`. Much cleaner. >>>>> >>>>> Not too hard to implement your own version of `Map.filter` though, so >>>>> I don't feel too strongly about it. >>>>> >>>>> On Thu, Aug 15, 2019 at 11:12 AM Alexei Sholik <alcos...@gmail.com> >>>>> wrote: >>>>> >>>>>> The simplest alternative is to use :maps.filter(). It's not as easy >>>>>> to pipe into, but that's a minor concern for me. >>>>>> >>>>>> As another alternative, this should be faster and have lower memory >>>>>> footprint than using Enum, although you'd need to benchmark it as well to >>>>>> be sure: >>>>>> >>>>>> map >>>>>> |> Stream.filter(predicate) >>>>>> |> Map.new() >>>>>> >>>>>> Personally, I would love to see an extension for Map.new() that would >>>>>> allow filtering the first argument in addition to the currently supported >>>>>> transformation. So instead of the current >>>>>> >>>>>> Map.new(enumerable, fn thing -> {key, val} end) >>>>>> >>>>>> we could have >>>>>> >>>>>> Map.new(enumerable, map: fn thing -> {key, val} end, filter: fn >>>>>> {_key, val} -> predicate(val) end) >>>>>> >>>>>> Such an extension is unlikely to be added though because it would be >>>>>> another way of doing what is already possible with Enum, Stream, and Map. >>>>>> >>>>>> On Thu, Aug 15, 2019 at 10:29 AM Roman Smirnov <pom...@gmail.com> >>>>>> wrote: >>>>>> >>>>>>> Since OTP 18 there is a pretty convenient function :maps.filter >>>>>>> <http://erlang.org/doc/man/maps.html#filter-2>. >>>>>>> >>>>>>> I think it would be nice to have Map.filter(map, predicate) in >>>>>>> Elixir as well instead of doing >>>>>>> >>>>>>> >>>>>>> map|> Enum.filter(predicate)|> Enum.into(%{}) >>>>>>> >>>>>>> >>>>>>> or >>>>>>> >>>>>>> for {key, value} <- map, some_filter(key, value), into: %{}, do: {key, >>>>>>> value} >>>>>>> >>>>>>> The first one alternative is slower, b/c of 2-step transformation, >>>>>>> and the second one consume more memory, could not be piped and has a >>>>>>> lack >>>>>>> of expressiveness (too imperative way to do a simple filtration). >>>>>>> There were benchmarks and a small discussion in PR: >>>>>>> https://github.com/elixir-lang/elixir/pull/9292, but the discussion >>>>>>> should be moved to this mailing list. >>>>>>> >>>>>>> >>>>>>> -- >>>>>>> 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 elixir-l...@googlegroups.com. >>>>>>> To view this discussion on the web visit >>>>>>> https://groups.google.com/d/msgid/elixir-lang-core/5d403c4a-91f8-4c4d-8dc0-297185a2aed8%40googlegroups.com >>>>>>> <https://groups.google.com/d/msgid/elixir-lang-core/5d403c4a-91f8-4c4d-8dc0-297185a2aed8%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>>>> . >>>>>>> >>>>>> -- >>>>>> 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 elixir-l...@googlegroups.com. >>>>>> To view this discussion on the web visit >>>>>> https://groups.google.com/d/msgid/elixir-lang-core/CAAPY6eO5aDifRxHxv7QtD4%3Di_bYbUw1sphxMhq4jEjuR9naPSQ%40mail.gmail.com >>>>>> <https://groups.google.com/d/msgid/elixir-lang-core/CAAPY6eO5aDifRxHxv7QtD4%3Di_bYbUw1sphxMhq4jEjuR9naPSQ%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>>> . >>>>>> >>>>> -- >>>>> 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 elixir-l...@googlegroups.com. >>>>> To view this discussion on the web visit >>>>> https://groups.google.com/d/msgid/elixir-lang-core/CAKL9qdTxQWdKDM7B%3D1XLkf7w9PeshpfSyrpsuhM%3DeaEqdZVSDA%40mail.gmail.com >>>>> <https://groups.google.com/d/msgid/elixir-lang-core/CAKL9qdTxQWdKDM7B%3D1XLkf7w9PeshpfSyrpsuhM%3DeaEqdZVSDA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> >>>> -- >>>> >>>> Andrea Leopardi >>>> an.le...@gmail.com >>>> >>> -- >>> 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 elixir-l...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/elixir-lang-core/c819a8cc-c3b6-41cc-a056-76a294b79fb6%40googlegroups.com >>> <https://groups.google.com/d/msgid/elixir-lang-core/c819a8cc-c3b6-41cc-a056-76a294b79fb6%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- > 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 elixir-lang-core+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/elixir-lang-core/13ab9f68-3895-47b1-bd7f-dee62f1a2e66%40googlegroups.com > <https://groups.google.com/d/msgid/elixir-lang-core/13ab9f68-3895-47b1-bd7f-dee62f1a2e66%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "elixir-lang-core" group. 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