Exception Handling

An exception is an event, which occurs during the execution of a program that disrupts the normal flow of the program's instructions. In general, when a Python script encounters a situation that it cannot cope with, it raises an exception. An exception is a Python object that represents an error.

Why Exception Handling?

Exception handling is essential in programming because it lets you manage unexpected errors that can occur during program execution. It ensures your program doesn't crash when encountering issues like dividing by zero or file not found. By handling exceptions, you create more robust and user-friendly programs, enable better debugging, and maintain control over potential problems. In Python, this approach aligns with its philosophy of embracing errors gracefully.

Exception handling in Python revolves around the use of four main blocks: try, except, else, and finally.

• try: Wrap the portion of code that might raise an exception within this block.

• except: Specify the type of exception you want to catch and define how to handle it.

• else: This block is executed if no exceptions occur within the try block.

• finally: Include cleanup code that must run regardless of whether an exception was caught.

Common Exception Types and Examples

1. ZeroDivisionError: Occurs when division or modulo operation is attempted with a denominator of zero.

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

2. ValueError: Raised when a function receives an argument of the correct type but with an inappropriate value.

    try:
        num = int("abc")
    except ValueError:
        print("Invalid input. Please enter a number.")
   

3. TypeError: Arises when an operation or function is applied to an object of inappropriate type.

    try:
        result = "hello" + 5
    except TypeError:
        print("Unsupported operation.")
   

4. FileNotFoundError: Triggered when an attempt is made to open a file that doesn't exist.

    try:
        with open("nonexistent.txt", "r") as file:
            content = file.read()
    except FileNotFoundError:
        print("File not found.")
   

   Exception Handling Best Practices

   1. Specificity: Catch specific exceptions to handle them effectively, rather than using a broad exception like Exception.

   2. Avoid Bare Except: Avoid using except: without specifying the exception type, as it can obscure bugs and hinder debugging.

   3. Minimalism: Catch only the exceptions you can handle. Allow unhandled exceptions to propagate for better troubleshooting.

   4. Logging: Utilize Python's logging module to record exception details for future analysis.