Re: [Haskell-cafe] getting last char of String

On Sat, 2011-01-01 at 19:27 +1100, Jesse Schalken wrote:

On Sat, Jan 1, 2011 at 8:54 AM, Felipe Almeida Lessa wrote: On Fri, Dec 31, 2010 at 6:43 PM, aditya siram wrote: > -- untested and won't work on an infinite list > last :: [a] -> a > last = head . reverse

No definition for last works with infinite lists =).

Unless you make the result nullable, of course.

maybeLast :: [a] -> Maybe a

maybeLast [] = Nothing maybeLast [x] = Just x maybeLast (_:xs) = maybeLast xs

It may or may not be expected but it may also be written as: maybeLast' [] = Nothing maybeLast' (x:xs) = Just (fromMaybe x (maybeLast xs)) The main differences are: maybeLast (x:_|_) = _|_ maybeLast' (x:_|_) = Just _|_ maybeLast (fix (x:)) = _|_ maybeLast' (fix (x:)) = Just _|_ Regards