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  • #9337

Closed
Open
Opened Jul 20, 2014 by JohnWiegley@trac-JohnWiegley

Add `sortOn` function to Data.List

This passed the vote on the libraries list a while ago, but I forget to add a ticket. The request was to add sortOn to Data.List:

-- | Sort a list using a key on each element.  This implements the
--   decorate-sort-undecorate paradigm, also called a Schwarzian transform.
sortOn :: Ord b => (a -> b) -> [a] -> [a]
sortOn f = map snd . sortBy (comparing fst) . map (\x -> (f x, x))
Trac metadata
Trac field Value
Version 7.8.3
Type FeatureRequest
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component libraries/base
Test case
Differential revisions
BlockedBy
Related
Blocking
CC ekmett, hvr
Operating system
Architecture
Assignee
Assign to
7.10.1
Milestone
7.10.1 (Past due)
Assign milestone
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None
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Reference: ghc/ghc#9337