Python Questions and Answers – While and For Loops – 4

This set of Python Questions & Answers focuses on “While and For Loops” and is useful for freshers who are preparing for their interviews.

1. What is the output of the following?

x = 123
for i in x:
    print(i)

a) 1 2 3
b) 123
c) error
d) none of the mentioned
View Answer

Answer: c
Explanation: Objects of type int are not iterable.

2. What is the output of the following?

d = {0: 'a', 1: 'b', 2: 'c'}
for i in d:
    print(i)

a) 0 1 2
b) a b c
c) 0 a 1 b 2 c
d) none of the mentioned
View Answer

Answer: a
Explanation: Loops over the keys of the dictionary.

3. What is the output of the following?

d = {0: 'a', 1: 'b', 2: 'c'}
for x, y in d:
    print(x, y)

a) 0 1 2
b) a b c
c) 0 a 1 b 2 c
d) none of the mentioned
View Answer

Answer: d
Explanation: Error, objects of type int aren’t iterable.

4. What is the output of the following?

d = {0: 'a', 1: 'b', 2: 'c'}
for x, y in d.items():
    print(x, y)

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a) 0 1 2
b) a b c
c) 0 a 1 b 2 c
d) none of the mentioned
View Answer

Answer: c
Explanation: Loops over key, value pairs.

5. What is the output of the following?

d = {0: 'a', 1: 'b', 2: 'c'}
for x in d.keys():
    print(d[x])

a) 0 1 2
b) a b c
c) 0 a 1 b 2 c
d) none of the mentioned
View Answer

Answer: b
Explanation: Loops over the keys and prints the values.

6. What is the output of the following?

d = {0: 'a', 1: 'b', 2: 'c'}
for x in d.values():
    print(x)

a) 0 1 2
b) a b c
c) 0 a 1 b 2 c
d) none of the mentioned
View Answer

Answer: b
Explanation: Loops over the values.

7. What is the output of the following?

d = {0: 'a', 1: 'b', 2: 'c'}
for x in d.values():
    print(d[x])

a) 0 1 2
b) a b c
c) 0 a 1 b 2 c
d) none of the mentioned
View Answer

Answer: d
Explanation: Causes a KeyError.

8. What is the output of the following?

d = {0, 1, 2}
for x in d.values():
    print(x)

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a) 0 1 2
b) None None None
c) error
d) none of the mentioned
View Answer

Answer: c
Explanation: Objects of type set have no attribute values.

9. What is the output of the following?

d = {0, 1, 2}
for x in d:
    print(x)

a) 0 1 2
b) {0, 1, 2} {0, 1, 2} {0, 1, 2}
c) error
d) none of the mentioned
View Answer

Answer: a
Explanation: Loops over the elements of the set and prints them.

10. What is the output of the following?

d = {0, 1, 2}
for x in d:
    print(d.add(x))

a) 0 1 2
b) 0 1 2 0 1 2 0 1 2 …
c) None None None
d) none of the mentioned
View Answer

Answer: c
Explanation: Variable x takes the values 0, 1 and 2. set.add() returns None which is printed.

11. What is the output of the following?

for i in range(0):
    print(i)

a) 0
b) (nothing is printed)
c) error
d) none of the mentioned
View Answer

Answer: b
Explanation: range(0) is empty.