/fp-sessions

Primary LanguageHaskell

#Problems

##Day 1

  1. rest: takes a list and returns all the elements except the first element
  2. last: takes a list and returns the last element
  3. count: takes a list and returns length of list
  4. elemAt: takes a list, an index and returns the element at that position e.g. elemAt 4 [1,2,3,4,5] = 5
  5. take: takes a list, a number and returns that many elements from the list. e.g. take 3 [1,2,3,4,5] = [1,2,3]ii
  6. drop: takes a list, a number and returns the list without that many elements from the list. e.g. drop 3 [1,2,3,i4,5] = [4,5]

##Day 2

  1. Create a function second that gives you the second element of a tuple
  2. Create a function zip that takes two lists and returns a tuple with elements from both the lists: zip [1,2,3] ['a','b','c'] = [(1,'a'),(2,'b'),(3,'c')]
  3. Create a function curry that takes function of type: (Int,Int) -> Int and returns a function in curried form: Int -> Int -> Int. So, if I say call curry addTuples, the result should be add where addTuple = \(a,b) -> a + b and add = \a b -> a + b.
  4. Create a function uncurry that does the opposite of above.
  5. Create a function flip that flips the arguments. If subtract x y = x - y, then flip subtract should be the equivalent of subtract x y = y - x.
  6. Create a function subtract that does subtraction. Subtract 2 from all numbers in a list using map and the subtract. First try it using anonymous functions and then try to use the flip defined above. Return a curried function.
  7. Create a list of functions: list :: [(Int -> Int)]. Put whatever functions you need.
  8. Map over the above list so that the resultant list contains all functions that return double the value of their counterparts in the earlier list.
  9. Apply composition over all the elements in the above list and return one function.

##Day 6 Implement Cycle Rental: write functions for listing all cycles, renting a cycle, returning a cycle and paying the rental price which is number of days taken for rent times the rent per day of the cycle taken on rent.

##Day 8

  1. Write an Identity typeclass. It should have an ident function that takes a value and gives it back.
  2. Is Identity a functor? If yes, create an instance of Functor for it.
  3. Implement Functor for BinaryTree that we wroter earlier.
  4. Write a function duration that takes a Rental that we defined in the cycle store problem and returns a Maybe Int. It should return Nothing if endDate is Nothing else it should return a value. Use fmap for writing this.