Handling specific exceptions in Python - Mini Project: Build & Apply

Handling specific exceptions

📖 Scenario: Imagine you are writing a small program that asks a user to enter two numbers and divides the first number by the second. Sometimes users might enter wrong data or try to divide by zero, which causes errors. We want to handle these errors carefully so the program does not crash and gives friendly messages.

🎯 Goal: You will build a program that safely divides two numbers by handling specific errors: ValueError when the input is not a number, and ZeroDivisionError when dividing by zero.

📋 What You'll Learn

Create two variables to store user input as numbers

Add a try-except block to catch ValueError and ZeroDivisionError

Print a friendly message for each specific error

Print the division result if no error occurs

💡 Why This Matters

🌍 Real World

Handling specific exceptions helps programs run smoothly even when users make mistakes, like entering wrong data or dividing by zero.

💼 Career

Knowing how to catch and handle errors is essential for writing reliable software that does not crash unexpectedly.

1

DATA SETUP: Create variables for user input

Create two variables called num1 and num2 by converting the strings '10' and '0' to integers using int().

Python

# Create variables num1 and num2 from strings '10' and '0'
# Your code here

Need a hint?

Use int('10') to convert the string '10' to the number 10.

2

CONFIGURATION: Prepare for error handling

Create a variable called result and set it to None. This will hold the division result later.

Python

num1 = int('10')
num2 = int('0')
# Create a variable result and set it to None
# Your code here

Need a hint?

Set result = None before trying the division.

3

CORE LOGIC: Use try-except to handle specific exceptions

Write a try block where you divide num1 by num2 and assign it to result. Add two except blocks: one for ZeroDivisionError that prints 'Cannot divide by zero.' and one for ValueError that prints 'Invalid number input.'.

Python

num1 = int('10')
num2 = int('0')
result = None
# Use try-except to divide num1 by num2
# Your code here

Need a hint?

Put the division inside try: and catch errors with except ZeroDivisionError: and except ValueError:.

4

OUTPUT: Print the division result if no error

After the try-except blocks, write an if statement that checks if result is not None. If so, print f'Result: {result}' to show the division result.

Python

num1 = int('10')
num2 = int('0')
result = None
try:
    result = num1 / num2
except ZeroDivisionError:
    print('Cannot divide by zero.')
except ValueError:
    print('Invalid number input.')
# Print the result if it is not None
# Your code here

Need a hint?

Use if result is not None: to check before printing.