Re: [Haskell-cafe] Combinations

Henning Thielemann wrote:

combinations = foldr (Monad.liftM2 (:)) [[]]

Lennart Augustsson wrote:

combinations [] = [[]] combinations (xs:xss) = liftM2 (:) xs (combinations xss)

List comprehension is faster when compiled with ghc-6.4.2 -O: combinations [] = [[]] combinations (xs:xss) = [ x:y | x <- xs, y <- combinations xss ] BTW, I think 'cross_many' would be a better name. -- -- Mirko Rahn -- Tel +49-721 608 7504 -- --- http://liinwww.ira.uka.de/~rahn/ ---