Output of Python Programs | Set 22 (Loops)

Prerequisite: Loops
Note: Output of all these programs is tested on Python3

1. What is the output of the following?

mylist = ['geeks', 'forgeeks']
for i in mylist:
    i.upper()
print(mylist)

1. [‘GEEKS’, ‘FORGEEKS’].
2. [‘geeks’, ‘forgeeks’].
3. [None, None].
4. Unexpected

Output:

2. [‘geeks’, ‘forgeeks’]

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?

mylist = ['geeks', 'forgeeks']
for i in mylist:
    mylist.append(i.upper())
print(mylist)

1. [‘GEEKS’, ‘FORGEEKS’].
2. [‘geeks’, ‘forgeeks’, ‘GEEKS’, ‘FORGEEKS’].
3. [None, None].
4. None of these

Output:

4. None of these

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

1. 1 2 3 4 5 6.
2. 1 2 3 4 5 6 7.
3. error.
4. None of these

Output:

1. 1 2 3 4 5 6

Explanation: The loop will terminate when i will be equal to 7.

4. What is the output of the following?

True = False
while True:
    print(True)
    break

1. False.
2. True.
3. Error.
4. None of these

Output:

3. Error

Explanation: SyntaxError, True is a keyword and it’s value cannot be changed.

5. What is the output of the following?

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

1. 1 2 3.
2. 1 2.
3. Syntax Error.
4. None of these

Output:

3. Syntax Error

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