built-in functions

• List:

  lst = [1,2,3,4,5] = 1:2:3:4:5:[]

  head lst = 1

  tail lst = [2,3,4,5]

  init lst = [1,2,3,4]

  last lst = 5
• example code of map:

  doSth :: (a -> b) -> [a] -> [b]

  doSth f [] = []

  doSth f (x:xs) = f x : doSth f xs
• example code of filter:

  doSth :: (a -> Bool) -> [a] -> [a]

  doSth p [] = []

  doSth p (x:xs)

  | p x = x : doSth p xs

  | otherwise = doSth p xs
• example of code of zip:

  doSth :: [a] -> [b] -> [(a,b)]

  doSth _ [] = []

  doSth [] _ = []

  doSth (x:xs) (y:ys) = (x,y) : doSth xs ys
• map (+1) [1..5] = [2,3,4,5,6]
• filter even [1..5] = [2,4]
• zip [1,2] [3,4,5] = [(1,3),(2,4)]
• zipWith (+) [1,2] [3,4,5] = [4,6]
• function that returns the first of a pair

  fst
• function that returns the second of a pair

  snd
• zip: combines two list to list of pairs
• unzip: splits a list of pairs into two lists
• filter: take elements that satisfy the condition and discard the rest.
• foldl: apply binary operator from left to right, accumulating result as it goes along.
• foldr: apply binary operator from right to left, accumulating result as it goes along.
• map: applies function to every element of list and return new list with modified values
• Returns the lowest of two arguments

  min
• Returns the highest of two arguments

  max