Sorting Arrays directly

andre-dietrich · December 14, 2021, 9:09pm

Hi, I was wondering, why there is sort function within the Array module. It seems to me, that the List module makes use of this feature by translating lists to arrays and back after sorting. Wouldn’t it be nice to expose the same functionality also to arrays directly? I know (Array.toList >> List.sort >> Array.fromList) would be an option, but I do not like the translation steps. Or, is it not such a huge performance issue?

github.com

elm/core/blob/84f38891468e8e153fc85a9b63bdafd81b24664e/src/Elm/Kernel/List.js#L73-L86

    
      
          var _List_sortBy = F2(function(f, xs)
          {
          	return _List_fromArray(_List_toArray(xs).sort(function(a, b) {
          		return __Utils_cmp(f(a), f(b));
          	}));
          });
          
          
var _List_sortWith = F2(function(f, xs)
          {
          	return _List_fromArray(_List_toArray(xs).sort(function(a, b) {
          		var ord = A2(f, a, b);
          		return ord === __Basics_EQ ? 0 : ord === __Basics_LT ? -1 : 1;
          	}));
          });

jfmengels · December 14, 2021, 9:22pm

I know ( Array.toList >> List.sort >> Array.fromList ) would be an option, but I do not like the translation steps. Or, is it not such a huge performance issue?

The performance of this would be “noticeable”, though likely only in benchmarks or extremely large lists.

I guess it would be a possible addition to the core Array API, but I am not privy to the details, and I don’t know if there a good reasons not to, or whether it’s intentional or something that was forgotten.

andre-dietrich · December 15, 2021, 6:01am

I thought so either (in performance), doing statistics would be a bit faster with arrays, if there would be more “native” functions like sort or sum or product … (at least sort and sum)

system · December 25, 2021, 6:02am

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Sorting Arrays directly

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