Extra Practice for Week 4 (Due never) Code Tracing (CT) Exercises


These problems will help you prepare for hw4 and quiz4. They are optional and you are encouraged to collaborate when working on them.
Code Tracing (CT)
What will each of these print?

  1. def ct(a, b): a += [3] a = a + [4] for c in a: for i in range(len(b)): if (b[i] not in a): print("A", end="") b[i] += c elif (c % 2 == 1): print("B", end="") b += [c] elif (b[-1] != c): print("C", end="") b = b + [c] return (a,b) a = [4] b = [2,3] print(ct(a,b)) print(a,b)

  2. def ct(L): result = [ ] M = [L[i]*10**i for i in range(len(L))] for val in M: result.extend([val, L.pop()]) return result L = [2,5,3] M = ct(L) print(L, M)

  3. def ct(L): result = [ ] M = L[:] # same as M = copy.copy(L) if (M == L): result.append(1) if (M is L): result.append(2) if (M[0] == L[0]): result.append(3) if (M[0] is L[0]): result.append(4) return result print(ct([5,7,6]))

  4. def ct(L): M = L L += [4] M = M + [5] print(L, M) ct(list(range(1)))

  5. import copy a = [1,2,3,4] (b,c) = (a, copy.copy(a)) print((a == b), (a == c)) print((a is b), (a is c)) print((a[0] is b[0]), (a[0] is c[0])) a = [1,2] (b,c) = (a, copy.copy(a)) b[0] += 10 c[1] += 100 for L in [a,b,c]: print(L) a = [1,2] (b,c) = (a, copy.copy(a)) a[0] += 1 b[0] += 2 c[1] += 3 a[0] = c[0] b[0] = a[1] for L in [a,b,c]: print(L) print() a = list(range(2,10,7)) (b, c) = (a, a[:2]) b[0] += 3 a += [3] a = a + [4] print(c + [b[0]]) print(c.append(b[1])) print(a, b, c)

  6. import copy def f(a, b): a = copy.copy(a) a[0] = b[1] b[0] = a[1] return a + b a1 = a2 = list(range(5,7)) b1 = b2 = list(range(2)) a1 = f(a1, b1) print(a1, a2, b1, b2)

  7. def onesDigit(n): return n%10 def ct(L): for i in range(len(L)): L[i] += sum(L) + max(L) return sorted(L, key=onesDigit) a = [2,1,0] print(ct(a)) print(a)

  8. def ct(a): a[1] = "foo" a[0], a[2] = a[2], a[0] print(a) b = a b.extend([42, "wow" ]) b.pop() print(b) c = [] + b c[1:-1] = ["Hello" , "World" ] return c lst = [15, "1" , "twelve" ] print(ct(lst)) print(lst)