[Haskell-cafe] Time consumption nub

Hi, Wondering about time space consuming: 'nub' vs 'map head.group.sort' Consider: ry = [1..10000] ++ replicate 13 5 ++ replicate 21 34 *Main> length . nub $ ry 10000 (5.18 secs, 1050000 bytes) *Main> length . map head . group . sort $ ry 10000 (0.03 secs, 6293384 bytes) Time space nub --- + fnub +++ - + is better ;-) Thanks @@i=arie