7/90: Learn Core Python in 90 Days — A Beginner’s Guide

Day 7: Exception Handling: Handling Errors Gracefully

Welcome to Day 7 of our 90-day journey to learn core Python! Yesterday, we explored file handling, an important aspect of working with external data. Today, we’ll dive into exception handling, a powerful technique for handling errors in our programs. Let’s get started!

What are Exceptions?

In Python, exceptions are events that occur during program execution, disrupting the normal flow. Examples include dividing by zero, accessing an invalid index, or opening a non-existent file. By handling exceptions, we can gracefully deal with these errors and prevent our program from crashing.

Handling Exceptions with try-except Blocks

To handle exceptions, we use try-except blocks. We enclose the code that may raise an exception within the try block. If an exception occurs, it’s caught by the except block, where we can define how to handle the error. Let’s see an example:

try:
    num = 10 / 0  # Potential division by zero error
except ZeroDivisionError:
    print("Error: Division by zero is not allowed.")

In this example, we catch the ZeroDivisionError exception and print a custom error message. There are many built-in exception types in Python, and we can also create custom exceptions.

Handling Multiple Exceptions

We can handle multiple exceptions by including multiple except blocks. Each except block specifies the type of exception it handles. Here’s an example:

try:
    # Code that may raise exceptions
except ValueError:
    # Handling ValueError
except TypeError:
    # Handling TypeError
except:
    # Handling all other exceptions

By handling specific exceptions, we can provide appropriate actions for different error scenarios.

Finally Block and Cleanup Actions

The finally block allows us to define code that will always be executed, regardless of whether an exception occurs or not. It’s commonly used for cleanup actions, such as closing files or releasing resources. Here’s an example:

try:
    # Code that may raise exceptions
finally:
    # Cleanup actions

The code in the finally block will be executed no matter what, ensuring proper cleanup in our programs.

Conclusion

Congratulations on completing Day 7 of our Python learning journey! Today, we explored exception handling, an essential technique to handle errors gracefully. By using try-except blocks, we can catch and handle exceptions, preventing our program from crashing.

Take some time to practice exception handling in your code. Tomorrow, on Day 8, we’ll delve into string manipulation and explore useful string methods.

Keep up the great work, and I’ll see you tomorrow for Day 8! Happy coding! 🚀

Note: This blog post is part of a 90-day series to teach core Python programming from scratch. If you missed any previous days, you can find them in the series index here.