99 questions/Solutions/4

Revision as of 01:39, 20 November 2010 by Drb226 (Talk | contribs)

(*) Find the number of elements of a list.

myLength           :: [a] -> Int
myLength []        =  0
myLength (_:xs)    =  1 + myLength xs

myLength'   =  foldl (\n _ -> n + 1) 0
myLength''  =  foldr (\_ n -> n + 1) 0
myLength''' =  foldr (\_ -> (+1)) 0

This is

length

Prelude