Raising exceptions in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this exception raising code?

Consider the following Python code that raises an exception. What will be printed when this code runs?

Python

def check_age(age):
    if age < 18:
        raise ValueError("Age must be at least 18")
    return "Access granted"

try:
    print(check_age(16))
except ValueError as e:
    print(f"Error: {e}")

A Access granted

B No output

C ValueError: Age must be at least 18

D Error: Age must be at least 18

💡 Hint

Think about what happens when raise is called inside the function and how the try-except block handles it.

The function check_age raises a ValueError when the age is less than 18. The try-except block catches this exception and prints the error message prefixed by "Error:".

❓ Predict Output

intermediate

What error does this code raise?

Look at this code snippet. What error will it raise when executed?

Python

def divide(x, y):
    if y == 0:
        raise ZeroDivisionError("Cannot divide by zero")
    return x / y

result = divide(10, 0)

A ZeroDivisionError: Cannot divide by zero

B ValueError: Cannot divide by zero

C TypeError: unsupported operand type(s)

D No error, returns 0

💡 Hint

Check the condition that triggers the raise statement and the type of exception raised.

The function explicitly raises a ZeroDivisionError with the message "Cannot divide by zero" when the divisor is zero.

❓ Predict Output

advanced

What is the output of this nested exception raising code?

Analyze this code that raises exceptions inside nested try-except blocks. What will be printed?

Python

def func():
    try:
        raise KeyError("Key missing")
    except KeyError:
        raise ValueError("Value error raised")

try:
    func()
except ValueError as e:
    print(f"Caught: {e}")

A Caught: Value error raised

B No output

C KeyError: Key missing

D Caught: Key missing

💡 Hint

Notice the exception raised inside the except block and which exception is caught outside.

The func raises a KeyError, which is caught and replaced by raising a ValueError. The outer try-except catches the ValueError and prints its message.

❓ Predict Output

advanced

What happens when this code raises an exception without a message?

What will be the output of this code that raises an exception without a message?

Python

try:
    raise RuntimeError
except RuntimeError as e:
    print(f"Caught an error: {e}")

A No output

B Caught an error:

C RuntimeError

D Caught an error: RuntimeError

💡 Hint

Check what the exception object e contains when no message is provided.

When an exception is raised without a message, its string representation is empty, so printing {e} shows an empty string after the colon.

🧠 Conceptual

expert

Which option correctly raises a custom exception with a message?

You want to create and raise a custom exception MyError with the message "Something went wrong". Which option does this correctly?

A

class MyError(Exception):
    pass

raise MyError

B

class MyError(Exception):
    def __init__(self):
        super().__init__("Something went wrong")

raise MyError()

C

class MyError(Exception): pass

raise MyError("Something went wrong")

D

class MyError(Exception):
    def __init__(self, msg):
        self.msg = msg

raise MyError("Something went wrong")

💡 Hint

Remember how to define a custom exception and pass a message when raising it.

Option C defines a custom exception class and raises it with a message directly. Option C requires calling MyError() without arguments but sets the message in __init__. Option C raises the class, not an instance, causing a TypeError. Option C does not call super().__init__, so the message is not set properly.