I have thought about this a couple of times but another discussion we keep having is to make Enum.sum/1 part of a protocol for performance and then we wouldn't be able to optimize it in the Enum.sum/2 variant. I wonder if that can be confusing. So for now, I would go the reduce route if you are really worried about performance here.
On Fri, Jul 23, 2021 at 6:51 AM Sabiwara Yukichi <sabiw...@gmail.com> wrote: > Hi! > > Recently I found myself several times in a situation where I needed to sum > from an enumerable after applying a transformation, e.g. sum one field from > a list of structs. > There is a temptation to use Enum.map(list, fun) |> Enum.sum() which > would be wasteful since it needs to build the intermediate list. > Enum.reduce(list, 0, &(fun.(&1) + &2) works but it is less > straightforward and less explicit about the intent. > > I wondered if Enum.sum(list, fun) (or Enum.sum_by(list, fun)?) could be a > nice addition that would be consistent with some other Enum functions such > as Enum.count/2, Enum.any?/2. What do you think? > > My branch for reference: > https://github.com/elixir-lang/elixir/compare/master...sabiwara:sum/2?expand=1 > > -- > 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/CANnyohZtg19ES%2B52KzCX%3DYnY-rgaLoNcnuRaCyrmtbMpTQ1NDg%40mail.gmail.com > <https://groups.google.com/d/msgid/elixir-lang-core/CANnyohZtg19ES%2B52KzCX%3DYnY-rgaLoNcnuRaCyrmtbMpTQ1NDg%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-lang-core+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/elixir-lang-core/CAGnRm4%2B5JXO-tt2JN5k-R_vmv8nOgw7bjzO%2BhXJ2CnanoAwp-A%40mail.gmail.com.
