Exception Handling in Python

Exception handling in Python is crucial for gracefully managing errors and exceptions during program execution to prevent crashes and recover from unexpected situations.

What are Exceptions?

Title	Concept	Code
Definition of Exceptions	Events that disrupt normal program flow, requiring specific handling.	Exception handling prevents program crashes and provides error information.
Importance of Exception Handling	Error Handling: Ensures graceful error management. Program Stability: Enhances program reliability.	Prevents abrupt terminations due to errors.

Common Types of Exceptions

SyntaxError
TypeError
NameError
ZeroDivisionError
IndexError
ValueError

How Exceptions are Handled

Try-Except Blocks
Try-Except-Else Blocks
Try-Except-Finally Blocks

Error Handling Mechanisms

Try-Except Blocks

Title	Concept	Code
Syntax and Basic Usage	Handles exceptions in specified code blocks.	try: # Code that may raise exceptions except ExceptionName: # Handle the exception
Handling Specific Exceptions	Catch specific exceptions for specialized handling.	try: # Code except ZeroDivisionError: # Handle ZeroDivisionError

Multiple Except Blocks

Title	Concept	Code
Handling Different Types of Exceptions	Handle various exceptions with separate except blocks.	try: # Code except Exception1: # Handle Exception1 except Exception2: # Handle Exception2
Defining Order of Exception Handling	Prioritize more specific exceptions for effective handling.	try: # Code except Exception1: # Handle Exception1 except Exception2: # Handle Exception2

Handling Multiple Exceptions

Title	Concept	Code
Handling Multiple Errors in a Single Except Block	Catch multiple exceptions within a single block.	try: # Code except (Exception1, Exception2): # Handle both exceptions
Using Tuple to Catch Multiple Exceptions	Use tuples to capture and manage multiple exceptions.	try: # Code except (Exception1, Exception2) as e: # Handle exceptions stored in 'e'

Try-Except-Else Blocks

Title	Concept	Code
Execution of Code in Else Block	Include code to execute if no exception is raised.	try: # Code except Exception1: # Handle Exception1 else: # Code for no exception
Common Use Cases	Success Indication: Utilize 'else' block for success indication.	try: # Code that may raise exceptions except ExceptionName: # Handle the exception else: # Code for no exceptions

Try-Except-Finally Blocks

Title

Concept

Code

Cleaning Up Activities in Finally Block

Ensure specific actions are always performed.

try:
    # Code that may raise exceptions
except ExceptionName:
    # Handle the exception
finally:
    # Clean-up code always runs

Usage of Finally Block

Resource Cleanup: Release resources in the 'finally' block.

try:
    # Code
except ExceptionName:
    # Handle the exception
finally:
    # Release resources

Raising and Creating Custom Exceptions

Raising Exceptions

Title	Concept	Code
Using the 'raise' Statement	Trigger exceptions programmatically for error handling.	if something_bad_happens: raise SomeException("Error Message")
Customizing Error Messages	Be Specific: Tailor detailed error messages for clarity.	raise ValueError("Custom error message")

Creating Custom Exceptions

Title	Concept	Code
Defining Custom Exception Classes	Create specialized exceptions to suit specific needs.	class CustomError(Exception): pass
Inheriting from Exception Class	Inheritance: Extend built-in exception classes effectively.	class CustomError(Exception): pass

Handling Exceptions in Functions

Function Calls within Try Blocks

Title

Concept

Code

Invoking Functions that May Raise Exceptions

Call functions that could potentially raise exceptions.

try:
    some_function()  # Function that may raise an exception
except ExceptionName:
    # Handle the exception

Handling Exceptions Inside Functions

Ensure functions internally handle errors gracefully.

def some_function():
    try:
        # Code that may raise exceptions
    except ExceptionName:
        # Handle the exception

Returning Error Information

Title

Concept

Code

Returning Errors as Values

Design functions to return error indicators when needed.

def some_function():
    try:
        # Code that may raise exceptions
    except ExceptionName as e:
        return False, e  # Return error status and exception

Using Error Codes or Messages

Informative Returns: Provide useful error information.

def some_function():
    try:
        # Code that may raise exceptions
    except ExceptionName as e:
        return {"error": "Something went wrong", "exception": str(e)}

Re-raising Exceptions

Title

Concept

Code

Preserving Exception Information

Pass exceptions for higher-level handling.

try:
    # Code that may raise exceptions
except ExceptionName as e:
    # Further processing or logging
    raise e  # Re-raise the exception

Re-raising Exceptions for Higher-level Handling

Exception Propagation: Pass errors for centralized handling.

try:
    # Code that may raise exceptions
except ExceptionName as e:
    # Further processing or logging
    raise e  # Pass the exception to a higher level

Exception Propagation and Chaining

Propagation of Exceptions

Passing Exceptions Up the Stack
Understanding the Flow of Exception Propagation

Chaining Exceptions

Sequencing Multiple Exceptions
Linking Exceptions for Improved Debugging

Best Practices in Exception Handling

Specificity in Exception Handling

Precise Error Handling
Avoid Wide Exception Coverage

Logging Exceptions

Capturing and Logging Errors
Importance of Detailed Logging

Graceful Error Messages

User-friendly Error Display
Enhancing User Experience

Consistent Error Handling

Standardized Handling Approaches
Ensuring Uniform Error Responses