Exception Handling

Exception handling is a mechanism in Python that allows you to gracefully handle errors that may occur during program execution. It helps prevent your program from crashing and provides a way to recover from unexpected situations.

The try-except Block:

The try-except block is the fundamental construct for exception handling in Python. It consists of a try block, where the code that might raise an exception is placed, and one or more except blocks to handle specific exceptions.

Python

try:

  # Code that might raise an exception

except ExceptionType:

  # Code to handle the exception

Common Exceptions:

• ZeroDivisionError: Raised when dividing by zero.

• TypeError: Raised when an operation is performed on an object of an inappropriate type.

• ValueError: Raised when a built-in operation or function receives an argument of an inappropriate type or value.

• IndexError: Raised when an index is out of range for a list, tuple, or string.

• KeyError: Raised when a dictionary key is not found.

• FileNotFoundError: Raised when a file is not found.

Example:

Python

try:

  num1 = int(input("Enter the first number: "))

  num2 = int(input("Enter the second number: "))

  result = num1 / num2

  print("Result:", result)

except  ZeroDivisionError:

  print("Cannot divide by zero.")

except ValueError:

  print("Invalid input. Please enter numbers.")

Best Practices:

• Use specific exception types to catch only the exceptions you expect.

• Provide informative error messages.

• Consider using try-except-finally blocks to ensure that cleanup code is always executed.

• Avoid excessive use of except blocks, as it can make your code harder to debug.

Additional Considerations:

• Custom Exceptions: You can create custom exceptions by defining new classes that inherit from the Exception class.

• Raising Exceptions: Use the raise keyword to raise exceptions manually.

• Context Managers: The with statement can be used to manage resources and automatically handle exceptions.

By understanding and effectively using exception handling in Python, you can write more robust and resilient programs.