Languages that support it via square brackets: Rust, Ruby, Javascript, Python, C, Julia.
I see your point, ultimately for me what is frustrating is when I have predefined data structures and we have a tool for "get the value at some point (i.e map keys)" so I can do `map[:key][:key]` but if I want to write `map[:key][0][:key][0]` I have to reorient the code entirely to use `get_in` or piped functions like `|> Map.get(:key)`. Getting a key out of a keyword list would be equally as slow as getting a list at an index, so it didn't seem to me like the purpose of the `[]` was to only do fast operations. There are plenty of cases where I need to get things positionally out of lists, the two that come to mind are handling various data structures that I got externally, like from an API (I can use bracket access until I get to a list then I can't) and testing. Often I'm testing that something at a very specific point in a produced data structure is a specific value. I.e "the tenth item at the path `foo[:bar]` is X". I can do that with pattern matching, but its only feasible to a point (like pattern matching the 10th item from a list does not look good). We can use `get_in` but we could also make that argument for everything and not have bracket access at all. It seems like a natural extension of that choice to give lists (and probably tuples) sensible behavior with bracket syntax. I'm not necessarily convinced that not having `list[i]` will ultimately convince people not to write those bad algorithms, because they can just as easily say ` List.at ( http://list.at/ ) (list, 1)`. But wether or not I'm convinced of that is not relevant đ On Thu, Sep 21, 2023 at 12:39 PM, Justin Wood < m...@ankhers.dev > wrote: > > > > >> It was pointed out that perhaps we don't do this to express that indexing >> a list is not fast in Elixir like it is in other languages, but I'm not >> sure if that is sufficient reason IMO to leave out a typically very >> standard feature of lists. >> >> >> >> Thoughts? >> >> > > > > Can you give an example of a language that supports this? In my > experience, languages do not provide this. > > > > In Haskell, you need to the non-standard !! operator. > > > > myList !! 5 > > > > OCaml does not provide a way to do this at all and you need to manually > iterate through the list to find the element you want (maybe other stdlibs > like Core provide something, but I have not used them) > > > > Racket has the list-ref function in order to accomplish this > > > > (list-ref my-list 3) > > > > Common Lisp has the nth function for this > > > > (nth 5 my-list) > > > > In comparison, Elixir has provided the Enum. at/ 2 ( http://enum.at/2 ) > function. > > > > > While I believe most languages do provide some facility to retrieve the > value at some index of a list, most do not provide it as square bracket > indexing you would see in other languages where arrays are more common > such as Ruby or Javascript. > > > > Justin > > > > > > -- > 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+unsubscribe@ googlegroups. com ( > elixir-lang-core+unsubscr...@googlegroups.com ). > To view this discussion on the web visit https:/ / groups. google. com/ d/ > msgid/ elixir-lang-core/ dc142043-83dc-48e6-8c3f-7a39c8376d0e%40app. fastmail. > com ( > https://groups.google.com/d/msgid/elixir-lang-core/dc142043-83dc-48e6-8c3f-7a39c8376d0e%40app.fastmail.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/lmtev59d.9a7191c8-acee-4bb9-9673-4c6db8277641%40we.are.superhuman.com.
