Also, sum/1 is easily replaceable with Enum.reduce(enum, &+/2). sum_by(enum, fun) could be written as:
Enum.reduce(enum, 0, &(fun.(&1) + &2)) If you use this a lot in your code, you can extract it to a function and it will maintain the same clarity as sum_by :). Andrea Leopardi an.leopa...@gmail.com On Fri, Feb 2, 2018 at 11:27 AM, Kelvin Raffael Stinghen < kelvin.sting...@gmail.com> wrote: > The thing with `x_by` functions is that they still return the whole list > (like in `sort_by`) or an element of it (like in `max_by`). > > Example right from `h Enum.max_by`: > > ```elixir > iex> Enum.max_by(["a", "aa", "aaa"], fn(x) -> String.length(x) end) > "aaa" > ``` > > `Enum.sum` totally changes the returning value type to another, so I guess > there is no point of having them since you can totally use the function > `map` on your enumerable to get what you want. For example: > > ```elixir > iex> [“a”, “aa”, “aaa”] |> Stream.map(&String.length/1) |> Enum.sum() > => 6 > ``` > > Best, > Kelvin Stinghen > kelvin.sting...@me.com > > On Feb 2, 2018, at 05:48, Alexey Chernenkov <a.y.chernen...@gmail.com> > wrote: > > I'm missing `Enum.sum_by/2` func. There are several other `xxx_by` methods > (e.g. `sort_by` and `max_by`). > > -- > 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/f7c51011-5ff4-4667-8125- > 75ced517887a%40googlegroups.com > <https://groups.google.com/d/msgid/elixir-lang-core/f7c51011-5ff4-4667-8125-75ced517887a%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. > 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/7D23AA55-92B7-4EAA-A062-09F6493C73C5%40gmail.com > <https://groups.google.com/d/msgid/elixir-lang-core/7D23AA55-92B7-4EAA-A062-09F6493C73C5%40gmail.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 elixir-lang-core+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/elixir-lang-core/CAM9Rf%2BLexw7Vu67NghkhxVEx5knuygA3OtAYG064y%3DSwSSCb-A%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
