Haskell - Definition of higher-order functions (1) P90677


Statement
 

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This problem explores the definition of high-order functions on lists. Implement the following functions that work as the original Haskell functions without using the original function eachself (i.e., you cannot use foldl to implement myFoldl but you can use it to implement myAll). Additionally. you can only use recursion to implement myFoldl, myFoldr, myIterate, myUntil and myZip.

  1. myFoldl :: (a -> b -> a) -> a -> [b] -> a
  2. myFoldr :: (a -> b -> b) -> b -> [a] -> b
  3. myIterate :: (a -> a) -> a -> [a]
  4. myUntil :: (a -> Bool) -> (a -> a) -> a -> a
  5. myMap :: (a -> b) -> [a] -> [b]
  6. myFilter :: (a -> Bool) -> [a] -> [a]
  7. myAll :: (a -> Bool) -> [a] -> Bool
  8. myAny :: (a -> Bool) -> [a] -> Bool
  9. myZip :: [a] -> [b] -> [(a, b)]
  10. myZipWith :: (a -> b -> c) -> [a] -> [b] -> [c]

Scoring

Each function scores 10 points.

Public test cases

  • Input

    myFoldl (+) 1 [1..5]
myFoldr (+) 1 [1..5]
take 10 $ myIterate (*2) 1
myUntil (>100) (*2) 1
myMap ("la "++) ["joana", "mireia"]
myFilter odd [1..10]
myAll odd [1,3,5,3,1]
myAny odd [2,4,6,8,10]
myZip [1..4] [1..3]
myZipWith (+) [1..4] [1..3]

    Output

    16
16
[1,2,4,8,16,32,64,128,256,512]
128
["la joana","la mireia"]
[1,3,5,7,9]
True
False
[(1,1),(2,2),(3,3)]
[2,4,6]
    • Information
    Author
    Albert Rubio / Jordi Petit
    Language
    English
    Translator
    Jordi Petit
    Original language
    Catalan
    Other languages
    Catalan
    Official solutions
    Haskell
    User solutions
    Haskell