Handling Exceptions with try and except

Handling Exceptions with try and except

In Python, you can handle exceptions using a try...except block. This structure allows you to gracefully manage exceptions and continue program execution without crashing. In this section, we'll explore how to use try and except to handle exceptions effectively.

1. The try...except Block

The try...except block is used to catch and handle exceptions. It has the following structure:

try:
    # Code that may raise an exception
except ExceptionType:
    # Code to handle the exception

Here's how it works:

• The code inside the try block is executed.
• If an exception of the specified ExceptionType occurs, the program jumps to the corresponding except block.
• The code inside the except block is executed to handle the exception.

2. Handling a Specific Exception

You can specify the type of exception to catch in the except block. For example, to catch a ValueError:

try:
    number = int("abc")
except ValueError:
    print("A ValueError occurred. Please enter a valid number.")

3. Handling Multiple Exceptions

You can catch multiple exception types by using multiple except blocks:

try:
    # Code that may raise an exception
except ExceptionType1:
    # Handle ExceptionType1
except ExceptionType2:
    # Handle ExceptionType2

This allows you to tailor your error-handling code to different exception scenarios.

4. The else Block

You can include an else block that is executed if no exceptions occur in the try block. This is useful for executing code when everything goes smoothly:

try:
    result = 10 / 2
except ZeroDivisionError:
    print("Cannot divide by zero.")
else:
    print("The result is:", result)

5. The finally Block

The finally block is always executed, whether an exception is raised or not. It is often used for cleanup operations, such as closing files or releasing resources:

try:
    # Code that may raise an exception
except ExceptionType:
    # Handle the exception
finally:
    # Code that always runs, e.g., cleanup code

6. Raising Exceptions

You can raise exceptions explicitly using the raise statement to signal specific error conditions in your code:

def divide(a, b):
    if b == 0:
        raise ZeroDivisionError("Cannot divide by zero")
    return a / b

7. Exception Objects

When an exception is raised, Python creates an exception object containing information about the exception. You can access this information using the as keyword in the except block:

try:
    result = 10 / 0
except ZeroDivisionError as e:
    print(f"Exception: {e}")

Handling exceptions with try and except is crucial for writing robust and reliable code. Proper error handling allows your program to gracefully respond to errors and prevent crashes.