Difference between revisions of "99 questions/Solutions/4"
< 99 questions | Solutions
Jump to navigation
Jump to search
(correction (foldl) and shortened version of foldr) |
|||
Line 8: | Line 8: | ||
<haskell> |
<haskell> |
||
− | myLength' = |
+ | myLength' = foldl (\n _ -> n + 1) 0 |
− | myLength'' = foldr (\ |
+ | myLength'' = foldr (\_ n -> n + 1) 0 |
+ | myLength''' = foldr (\_ -> (+1)) 0 |
||
</haskell> |
</haskell> |
||
Revision as of 01:39, 20 November 2010
(*) 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
in Prelude
.