Exception Handling
Master error handling in Python. Learn try/except/finally, custom exceptions, and defensive programming.
Master error handling in Python. Learn try/except/finally, custom exceptions, and defensive programming. This hands-on tutorial focuses on practical implementation of exception handling concepts.
Exception Handling
Errors happen. Good programmers handle them gracefully instead of letting programs crash.
Common Exception Types
| Exception | When It Occurs |
|---|---|
ValueError | Invalid value (e.g., int("abc")) |
TypeError | Wrong type (e.g., "2" + 2) |
KeyError | Missing dictionary key |
IndexError | Invalid list index |
FileNotFoundError | File doesn't exist |
ZeroDivisionError | Division by zero |
AttributeError | Invalid attribute access |
Basic Try/Except
Try/Except/Else/Finally
Catching Multiple Exceptions
Raising Exceptions
Custom Exception Classes
Exception Chaining
Best Practices ✅
Coding Challenge: Input Validator
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Quiz
Quiz
Question 1 of 5When does the 'finally' block execute?
Key Takeaways
✅ Use try/except to handle errors gracefully.
✅ finally always executes (cleanup code).
✅ Catch specific exceptions, not everything.
✅ raise to throw exceptions.
✅ Create custom exceptions by inheriting from Exception.
What's Next?
In the next lesson, we'll learn about Working with JSON & CSV - essential data formats for modern applications.
Keep coding! 🚀