How to get every Nth element of an infinite list in Haskell?

Question

More specifically, how do I generate a new list of every Nth element from an existing infinite list?

E.g. if the list is [5, 3, 0, 1, 8, 0, 3, 4, 0, 93, 211, 0

Answer 1

This seems a slightly better use of unfold:

everyNth :: Int -> [a] -> [a]
everyNth n = unfoldr g
  where
    g [] = Nothing
    g xs = let (ys, zs) = splitAt n xs in Just (head ys, zs)

Or even better, use Data.List.Spit:

everyNth n = (map head) . chunksOf n