(**) Extract a slice from a list.
Given two indices, i and k, the slice is the list containing the elements between the i'th and k'th element of the original list (both limits included). Start counting the elements with 1.
slice xs (i+1) k = take (k-i) $ drop i xs
The same solution as above, but with guards:
slice  _ _ =  slice xs k n | k == n =  | k > n = error "k > n" | k == 0 = take n xs | otherwise = drop (k-1) $ take n xs
Or, an iterative solution:
slice :: [a]->Int->Int->[a] slice lst 1 m = slice' lst m  where slice' :: [a]->Int->[a]->[a] slice' _ 0 acc = reverse acc slice' (x:xs) n acc = slice' xs (n - 1) (x:acc) slice (x:xs) n m = slice xs (n - 1) (m - 1)
slice :: [a] -> Int -> Int -> [a] slice (x:xs) i k | i > 1 = slice xs (i - 1) (k - 1) | k < 1 =  | otherwise = x:slice xs (i - 1) (k - 1)
Another way using
splitAt, though not nearly as elegant as the
slice :: [a] -> Int -> Int -> [a] slice xs i k = chunk where chop = snd $ splitAt i' xs -- Get the piece starting at i chunk = fst $ splitAt (k - i') chop -- Remove the part after k i' = i - 1