[Haskell-beginners] How to select items from one list depending on another

[David Virebayre]

2010/11/10 C K Kashyap <ckkashyap at gmail.com>:
> Hi,
> I have this problem at hand -
>
> Given two lists
>
> list1 = [0,1,2,0,1,4]
>
> list2 = [1,2,3,4,5,6]
> I need to take items from the second list only when the corresponding
> item in list1 is non-zero.

Another wayOne way to do it, although not shorter :

list3 = catMaybes $ zipWith (\a b -> if a > 0 then Nothing else Just
b) list1 list2

David.