Re: [Haskell-cafe] A function that makes list of Bool lists from list of Int lists

Excerpts from Maur Toter's message of Sat Apr 03 09:54:26 -0400 2010:

I am new with Haskell so I think this will be a pretty dumb question. I would like to make a function that makes this:

listbool :: [[Int]] -> [[Bool]]

in this way: listbool [[1,2],[3,4]] == [[True, True],[False, False]] listbool [[1],[5,5],[5,4],[2]] == [[True],[False, False],[True, True], [False]]

So always True from the elements of the first list, False from the elements of the second one, etc...

Sure you can do this. In fact, the type can be more general: listbool :: [[a]] -> [[Bool]] listbool xs = zipWith ($) (map (\x -> map (const x)) (cycle [True, False])) xs Cheers, Edward