Adam Vogt wrote: > * On Saturday, December 13 2008, Gianfranco Alongi wrote: >> I have actually been thinking about a similar thing, but on the "group" >> subject. >> One can actually group things in many ways, such as groupBy (==) , so >> that groupBy (==) [1,2,1,2] should give >> [[1,1],[2,2]]. Of course other ideas are possible. > > That result happens with: > >> sortedGroups = group . sort > > That composition is pretty, unlike those splitting functions. I don't know > if manually fusing sort and group helps performance at all though.
Sorting requires an Ord instance, though. Here's a relatively simple but slow way which doesn't: fullGroupBy :: (a -> a -> Bool) -> [a] -> [[a]] fullGroupBy rel xs = map (\a -> filter (rel a) xs) (nubBy rel xs) _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
