Try–except–finally behavior in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of try-except-finally with exception

What is the output of this Python code?

Python

try:
    print("Start")
    x = 1 / 0
except ZeroDivisionError:
    print("Caught division by zero")
finally:
    print("Finally block executed")

A Start\nFinally block executed

B Caught division by zero\nFinally block executed

C Start\nCaught division by zero\nFinally block executed

D Start\nCaught division by zero

💡 Hint

Remember that the finally block always runs, even if an exception occurs.

The code prints "Start" first. Then it tries to divide by zero, which raises ZeroDivisionError. The except block catches it and prints "Caught division by zero". Finally, the finally block runs and prints "Finally block executed".

❓ Predict Output

intermediate

Return value with try-except-finally

What is the output of this Python code?

Python

def func():
    try:
        return 'try'
    except:
        return 'except'
    finally:
        return 'finally'

print(func())

A finally

B except

C None

D try

💡 Hint

The finally block runs after return statements and can override the return value.

Even though the try block returns 'try', the finally block runs last and its return value 'finally' overrides the previous return.

🧠 Conceptual

advanced

Exception propagation with finally

Consider this code snippet. What will be printed?

Python

def test():
    try:
        raise ValueError('error')
    finally:
        print('In finally')

try:
    test()
except Exception as e:
    print(f'Caught: {e}')

A In finally\nCaught: error

B Caught: error\nIn finally

C In finally

D Caught: error

💡 Hint

The finally block runs before the exception is caught outside.

The function test raises a ValueError. Before the exception leaves test, the finally block prints 'In finally'. Then the exception is caught in the outer try-except and prints 'Caught: error'.

❓ Predict Output

advanced

Exception in finally block

What happens when an exception is raised in the finally block?

Python

try:
    print('Try block')
    raise ValueError('Original error')
except ValueError as e:
    print(f'Caught: {e}')
finally:
    print('Finally block')
    raise RuntimeError('Error in finally')

A Try block\nFinally block\nCaught: Original error

B Try block\nCaught: Original error\nFinally block

C Try block\nCaught: Original error

D Try block\nCaught: Original error\nFinally block\nRuntimeError: Error in finally

💡 Hint

Exceptions in finally override previous exceptions.

The try block raises ValueError, which is caught and printed. The finally block runs and prints 'Finally block', but then raises RuntimeError. This new exception replaces the original one and is shown after the prints.

🔧 Debug

expert

Identify the output and explain the flow

What is the output of this code and why?

Python

def f():
    try:
        print('A')
        raise Exception('E1')
    except Exception as e:
        print('B')
        raise Exception('E2')
    finally:
        print('C')

try:
    f()
except Exception as e:
    print(f'D: {e}')

A A\nB\nD: E2\nC

B A\nB\nC\nD: E2

C A\nC\nB\nD: E2

D A\nC\nD: E1

💡 Hint

The finally block runs after the except block but before the exception propagates.

The function prints 'A', then raises 'E1'. The except catches it, prints 'B', and raises 'E2'. Before 'E2' propagates, the finally block runs and prints 'C'. Outside, the try-except catches 'E2' and prints 'D: E2'.