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Diffstat (limited to 'Haskell-book/10/Exercise.hs')
| -rw-r--r-- | Haskell-book/10/Exercise.hs | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/Haskell-book/10/Exercise.hs b/Haskell-book/10/Exercise.hs new file mode 100644 index 0000000..8207e5e --- /dev/null +++ b/Haskell-book/10/Exercise.hs @@ -0,0 +1,53 @@ +module Exercise where + +stops :: String +stops = "pbtdkg" + +vowels :: String +vowels = "aeiou" + +stopVowelStop :: [(Char, Char, Char)] +stopVowelStop = filter p [(x, y, z) | x <- stops, y <- vowels, z <- stops] + where p (a, _, _) = a == 'p' + +seekritFunc :: String -> Double +seekritFunc x = (/) (fromIntegral (sum (map length (words x)))) (fromIntegral (length (words x))) + +myAnd :: [Bool] -> Bool +myAnd = foldr (&&) True + +myOr :: [Bool] -> Bool +myOr = foldr (||) False + +myAny :: (a -> Bool) -> [a] -> Bool +myAny f = myOr . map f + +myElem :: Eq a => a -> [a] -> Bool +myElem x = foldr (\y z -> z || (y == x)) False + +myElem' :: Eq a => a -> [a] -> Bool +myElem' needle = any (\x -> x == needle) + +myReverse :: [a] -> [a] +myReverse = foldl (flip (:)) [] + +myMap :: (a -> b) -> [a] -> [b] +myMap f = foldr (\x y -> (f x) : y) [] + +myFilter :: (a -> Bool) -> [a] -> [a] +myFilter f = foldr (\x xs -> if f x then x : xs else xs) [] + +squish :: [[a]] -> [a] +squish = foldr (++) [] + +squishMap :: (a -> [b]) -> [a] -> [b] +squishMap f xs = foldr (++) [] (map f xs) + +squishAgain :: [[a]] -> [a] +squishAgain = squishMap id + +myMaximumBy :: (a -> a -> Ordering) -> [a] -> a +myMaximumBy f (z:zs) = foldl (\x y -> if (f x y) == GT then x else y) z zs + +myMinimumBy :: (a -> a -> Ordering) -> [a] -> a +myMinimumBy f (z:zs) = foldl (\x y -> if (f x y) == LT then x else y) z zs |
