Advanced Python Tutorial 2: Exception Handling and Debugging

🎯 Introduction

In professional Python development, handling exceptions gracefully and using debugging tools effectively are critical skills. Let's master these essentials!

🚧 What Are Exceptions?

Exceptions are errors that disrupt the normal flow of a program. Python handles them using try-except blocks.

try: num = int(input("Enter a number: ")) result = 100 / num print("Result:", result) except ZeroDivisionError: print("❌ Cannot divide by zero.") except ValueError: print("❌ Please enter a valid number.") except Exception as e: print(f"❌ Unexpected error: {e}")

🎭 Custom Exceptions

You can define your own exceptions for cleaner, domain-specific error handling.

class NegativeNumberError(Exception):
"""Custom exception for negative inputs."""
pass

def process_number(n):
if n < 0:
raise NegativeNumberError("Negative numbers are not allowed.")
return n * 2

try:
print(process_number(-5))
except NegativeNumberError as e:
print("❗ Error:", e)

🕵️ Debugging with pdb

pdb is Python’s built-in debugger. It allows stepping through code, inspecting variables, and identifying issues.

import pdb

def divide(a, b):
pdb.set_trace() # 🛑 Sets a breakpoint
return a / b

divide(10, 0)

📋 Best Practices

• ✅ Catch specific exceptions, not just except:.
• ✅ Use finally for cleanup (closing files, DB connections).
• ✅ Log exceptions using Python’s logging module in real applications.

🔎 SEO and AdSense Tips

• Use headings and semantic tags.
• Target keywords like “python debugging tutorial”.
• Ensure mobile responsiveness and fast load times.

✅ Summary

• Mastered try-except structure.
• Learned to build custom exceptions.
• Used pdb for step-by-step debugging.

Keep practicing to become confident with exception handling in real-world Python apps!