On 2010-09-10, at 10:55 , Lorenzo Isella wrote:
Dear All, I know this must be a one-liner, but it am banging my head against the wall. I am trying my hands at list manipulation in Haskell and a lot of useful function are making my life easier but I cannot achieve something really simple. Let us say you have the lists ml and sel
ml=[23,44,55,8,98] and sel=[1,2] .
Now, I would like simply to get a new list whose entries are the elements of ml in position sel. In my case things might be a little more complicated because all the elements are Integer and not Int (I noticed that sometimes this means I have to resort to generic functions). Cheers
What about nested list comprehensions: [x|(x,y)<-zip ml [x `elem` sel | x <- [1..maximum sel]], y] Henry