Effective Error Handling in Python

Learn how to handle errors and exceptions in Python effectively, including try-except blocks, custom exceptions, and logging.

Effective Error Handling in Python  

Error handling is an essential aspect of robust programming. This guide will teach you how to handle errors and exceptions in Python effectively using try-except blocks, custom exceptions, and logging.

Try-Except Blocks  

Basic Error Handling  

Use try-except blocks to catch and handle exceptions.

try:
    result = 10 / 0
except ZeroDivisionError:
    print("Cannot divide by zero")

Catching Multiple Exceptions  

Handle multiple exceptions in a single block.

try:
    result = 10 / 0
except (ZeroDivisionError, ValueError):
    print("An error occurred")

Finally Block  

Use the finally block to execute code regardless of the exception.

try:
    file = open("example.txt", "r")
finally:
    file.close()

Custom Exceptions  

Define your own exception classes for specific error handling.

class CustomError(Exception):
    def __init__(self, message):
        self.message = message

try:
    raise CustomError("This is a custom error")
except CustomError as e:
    print(e.message)

Custom exceptions can include additional functionality.

class CustomError(Exception):
    def __init__(self, message, error_code):
        super().__init__(message)
        self.error_code = error_code

try:
    raise CustomError("This is a custom error", 404)
except CustomError as e:
    print(f"Error: {e.message}, Code: {e.error_code}")

Logging  

Use logging for better error tracking and debugging.

import logging

logging.basicConfig(level=logging.DEBUG)
try:
    result = 10 / 0
except ZeroDivisionError:
    logging.error("Cannot divide by zero")

Logging can include different levels of severity.

logging.debug("Debug message")
logging.info("Info message")
logging.warning("Warning message")
logging.error("Error message")
logging.critical("Critical message")

Conclusion  

Effective error handling makes your code more reliable and easier to debug. Practice using try-except blocks, custom exceptions, and logging to manage errors gracefully in your Python applications.