While and For Loops 

This set of Python Multiple Choice Questions & Answers (MCQs) focuses on “While and For Loops”.
1. What is the output of the following?

x = ['ab', 'cd']
for i in x:
    i.upper()
print(x)

a) [‘ab’, ‘cd’]
b) [‘AB’, ‘CD’]
c) [None, None]
d) none of the mentioned
View Answer

Answer: a
Explanation: The function upper() does not modify a string in place, it returns a new string which isn’t being stored anywhere.

2. What is the output of the following?

x = ['ab', 'cd']
for i in x:
    x.append(i.upper())
print(x)

a) [‘AB’, ‘CD’]
b) [‘ab’, ‘cd’, ‘AB’, ‘CD’]
c) [‘ab’, ‘cd’]
d) none of the mentioned
View Answer

Answer: d
Explanation: The loop does not terminate as new elements are being added to the list in each iteration.

3. What is the output of the following?

i = 1
while True:
    if i%3 == 0:
        break
    print(i)
    i + = 1

a) 1 2
b) 1 2 3
c) error
d) none of the mentioned
View Answer

Answer: c
Explanation: SyntaxError, there shouldn’t be a space between + and = in +=.

4. What is the output of the following?

i = 1
while True:
    if i%0O7 == 0:
        break
    print(i)
    i += 1

a) 1 2 3 4 5 6

b) 1 2 3 4 5 6 7

c) error

d) none of the mentioned

View Answer

Answer: a
Explanation: Control exits the loop when i becomes 7.