I wrote: > When you can assume Ord, the standard solution > is, as you suggest, something like...
Oops, sorry, doesn't typecheck. Here it is corrected: > import qualified Data.Map as M > import Data.List > > histogram = M.toList . foldl' (\m x -> M.insertWith' (+) x 1 m) M.empty > This should work efficiently, with the right amount of laziness, even > for very large lists. Stuart's Arrows thing is much nicer when your list is small enough to be held in memory all at once. -Yitz _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
