Python Block Structure and Indentation - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of nested if-else with indentation

What is the output of this Python code snippet?

Python

x = 5
if x > 3:
    if x < 10:
        print("A")
    else:
        print("B")
else:
    print("C")

A B

B A

C C

D No output

💡 Hint

Check which conditions are true and how indentation groups the print statements.

The first if (x > 3) is true, then the nested if (x < 10) is also true, so it prints "A".

❓ Predict Output

intermediate

Effect of wrong indentation on loop execution

What will be printed by this code?

Python

for i in range(3):
    print(i)
  print('Done')

A IndentationError

B SyntaxError

C

0
1
2
Done

D

0
1
2

💡 Hint

Look carefully at the indentation of the last print statement.

The last print is indented less than the for loop block but not aligned with it, causing IndentationError.

❓ Predict Output

advanced

Output of function with mixed indentation

What is the output of this code?

Python

def f():
    x = 1
    if x == 1:
        print('Yes')
     print('No')
f()

A IndentationError

B

Yes
No

C Yes

D No

💡 Hint

Check the indentation of the second print inside the function.

The second print is indented with 5 spaces, which is inconsistent and causes IndentationError.

❓ Predict Output

advanced

Output of code with multiple blocks and else

What will this code print?

Python

for i in range(2):
    if i == 0:
        print('Zero')
    else:
        print('Not zero')
    print('Loop done')

A

Zero
Loop done
Not zero

B

Zero
Not zero
Loop done
Loop done

C

Zero
Not zero
Loop done

D

Zero
Loop done
Not zero
Loop done

💡 Hint

Notice the indentation of the last print statement inside the loop.

The last print is inside the loop but outside the if-else, so it runs every iteration after the if-else.

🧠 Conceptual

expert

Identifying the cause of unexpected output due to indentation

Consider this code: x = 10 if x > 5: print('Big') if x > 8: print('Very big') else: print('Small') Why does it print only "Big" and "Very big" and never "Small"?

A Because Python ignores else blocks after nested ifs.

B Because the else belongs to the second if, which is true, so else is skipped.

C Because the else belongs to the first if, and x > 5 is true, so else is skipped.

D Because indentation is wrong and else is outside any if.

💡 Hint

Check which if the else is paired with based on indentation.

The else is aligned with the first if, so it runs only if x > 5 is false. Since x=10 > 5, else is skipped.