Hi, I am trying to write a partition function where we pass group sizes and the list we want to partition into groups as arguments and get back a list of groups (or list of lists in this case). My first attempt was by using an auxiliary inner function {-# LANGUAGE ScopedTypeVariables #-} module Partition where partition :: [Int] -> [a] -> [[a]] partition ds ps = reverse $ paux ds ps [] where paux :: [Int] -> [a] -> [[a]] -> [[a]] paux [] [] ps' = ps' paux [] ps ps' = [ps] ++ ps’ paux _ [] ps' = ps' paux (d:ds') ps ps' = paux ds' (snd (splitAt d ps)) ([fst (splitAt d ps)] ++ ps') —————— *Partition> partition [2, 3] [1,2,3,4,5] [[1,2],[3,4,5]] *Partition> partition [1, 2] [1,2,3,4,5] [[1],[2,3],[4,5]] *Partition> partition [1, 2, 5] [1,2,3,4,5] [[1],[2,3],[4,5]] I was speculating if we could write the same function using foldl function but haven’t been able to figure it out. I would really appreciate if you can give me pointers on how we can implement it. partition' :: [Int] -> [a] -> [[a]] partition' [] ds = [ds] partition' ps ds = foldl ??? ???' ???'' contrary to my speculation is it even possible to write such a function using foldl if so why not? Regards, Apoorv Ingle Graduate Student, Computer Science apoorv.ingle@ku.edu mailto:apoorv.ingle@ku.edu