ACTSC231 Lecture 27: ACTSC231 Lecture Notes 27

Part (a) [3 MARKS] Consider this program: Fill in the Python Shell output after this program has executed. >>> X L = [4, 10, 8] X = L. sort L.append(20) L2 = L[1:] >>> L >>> id(L) == id(L2)

Question 11. [5 MARKS] Each code fragment in the table below operates on list L, which has length k where k is very large - at least in the tens of thousands. For each fragment, give an expression in terms of k for how many times happy! is printed, and circle whether the behaviour is constant, linear, quadratic or something else. Code How many times is happy! printed? Complexity (circle one) for i in range (len (L)): print('happy!') for item in L: print('happy!') constant linear quadratic something else for i in range (len(L)) for item in L[:i]: print('happy!' constant linear quadratic something else # Precondition: len(L) % 10 == 0 i = 0 while i < len(L): print("happy!') i = i + len(L) // 10 constant linear quadratic something else for item in L[1000:2000] : print('happy!' constant linear quadratic something else for item in L[10:] : print('happy!' constant linear quadratic something else

Part (b) [3 MARKS] Complete the function body according to its docstring description. You will be marked only on the parts that need to be different from (a). def count_letter_case_mutate (L): " (list of list of str) -> None Type Precondition: each str in L is non-empty and contains only alphabetic characters Replace each item in L with a two-item tuple in which the first item is the number of words in the list at the corresponding index of L that start with a lowercase letter and the second item is the number of words in the list at the corresponding index of L that start with an uppercase letter >>> data = [['apple', 'Banana'], ['PeAr'], [], ['PEACH', 'aprICot', 'plum']] >>> count_letter_case_mutate (data) >>> data [(1, 1), (0, 1), (0, 0), (2, 1)]