unfoldrでevery関数
http://www.hyuki.com/haskell/200412#i20041222095833
every' n xs = unfoldr f xs where f [] = Nothing f cs = Just (splitAt n cs)
Maybeの有り難さがちょっと分かった
http://www.hyuki.com/haskell/200412#i20041222095833
every' n xs = unfoldr f xs where f [] = Nothing f cs = Just (splitAt n cs)
Maybeの有り難さがちょっと分かった