As Daniel pointed out earlier, this may be of a little bit of help: http://haskell.org/ghc/docs/latest/html/libraries/base-4.2.0.0/src/Data-List.html#subsequences
On 18 March 2010 04:03, Alexander Solla <a...@2piix.com> wrote: > > On Mar 17, 2010, at 8:33 PM, zaxis wrote: > > >> `allPairs list = [(x,y) | x <- list, y <- list] ` is not what >> `combination` >> does ! >> >>> let allPairs list = [(x,y) | x <- list, y <- list] >>> allPairs [1,2,3] >>> >> [(1,1),(1,2),(1,3),(2,1),(2,2),(2,3),(3,1),(3,2),(3,3)] >> > > Yeah, I know that. I said so specifically. combination computes the power > set of a list. You said your goal was to compute a set of "two groups". > You don't need the power set in order to compute a set of pairs. Moreover, > computing the power set is a slow operation. Indeed, it is the source of > your slowness. > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > -- Ozgur Akgun
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