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More efficient version of filterAttrs

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This commit is contained in:
Eelco Dolstra 2015-07-23 16:12:25 +02:00
parent 2b2e7c2730
commit 3cd5fd8bb3
1 changed files with 1 additions and 1 deletions
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2
lib/attrsets.nix
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@ -76,7 +76,7 @@ rec {
=> { foo = 1; }
*/
filterAttrs = pred: set:
listToAttrs (fold (n: ys: let v = set.${n}; in if pred n v then [(nameValuePair n v)] ++ ys else ys) [] (attrNames set));
listToAttrs (concatMap (name: let v = set.${name}; in if pred name v then [(nameValuePair name v)] else []) (attrNames set));
/* foldAttrs: apply fold functions to values grouped by key. Eg accumulate values as list: