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author | Joe Zhao <ztuowen@gmail.com> | 2015-01-29 16:29:05 +0800 |
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committer | Joe Zhao <ztuowen@gmail.com> | 2015-01-29 16:29:05 +0800 |
commit | 0135b3ac0d41dda2a4c210e7c3989f20b672be5d (patch) | |
tree | 7284971efac168e9c704ec74e50cf4ce66df6916 | |
parent | edcc6ba8ca9d6b883b59548eb8bb5e312c73f43b (diff) | |
download | h99-0135b3ac0d41dda2a4c210e7c3989f20b672be5d.tar.gz h99-0135b3ac0d41dda2a4c210e7c3989f20b672be5d.tar.bz2 h99-0135b3ac0d41dda2a4c210e7c3989f20b672be5d.zip |
p1+ p2
-rw-r--r-- | p1.hs | 4 | ||||
-rw-r--r-- | p2.hs | 11 |
2 files changed, 15 insertions, 0 deletions
@@ -3,3 +3,7 @@ myLast :: [a] -> a myLast [] = error "Empty List" myLast [x] = x myLast (x:xs) = myLast xs + +myLast' = foldl1 (flip const) + +myLast'' = foldl1 (curry snd) @@ -0,0 +1,11 @@ +import Data.Foldable as F + +myButLast :: Foldable f => f a -> a + +myButLast = fst . F.foldl (\(a,b) x -> (b,x)) (err1, err2) + where + err1 = error "Empty list" + err2 = error "Not enough elements" + +mySafeButLast :: Foldable f => f a -> Maybe a +mySafeButLast = fst . F.foldl (\(a,b) x -> (b,Just x)) (Nothing, Nothing) |