99 questions/Solutions/4
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(Difference between revisions)
| Line 8: | Line 8: | ||
<haskell> | <haskell> | ||
| - | myLength' | + | myLength' = foldl (\n _ -> n + 1) 0 |
| - | myLength'' = foldr (\_ n -> n + 1) 0 | + | myLength'' = foldr (\_ n -> n + 1) 0 |
| - | myLength''' = foldr (\_ -> (+1)) 0 | + | myLength''' = foldr (\_ -> (+1)) 0 |
myLength'''' = foldr ((+) . (const 1)) 0 | myLength'''' = foldr ((+) . (const 1)) 0 | ||
</haskell> | </haskell> | ||
Revision as of 23:08, 12 January 2011
(*) 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 myLength'''' = foldr ((+) . (const 1)) 0
myLength' xs = snd $ last $ zip xs [1..] -- Just for fun
length
Prelude
