Handle Exceptions and Errors in Python

How to Handle Exceptions and Errors in Python?

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Exception handling is a essential concept in programming that deals with managing errors that occur during the execution of a program. In Python, errors are classified into syntax errors and exceptions. Syntax errors occurs when the code is not written correctly, while exceptions are runtime errors that arise during the execution of the program. Effective exception handling helps in debugging and ensuring smooth operation by allowing the program to recover from errors and continue running. Are you looking to advance your career in Python? Get started today with the Python Training in Chennai from FITA Academy!

Understanding Python Exceptions

In Python, exceptions are events that can modify the flow of control through a program. They are represented by objects and can be caught and handled using try-except blocks. The most common types of exceptions include:

  • SyntaxError: Raised when there is an error in the syntax of the code.
  • TypeError: Raised when an operations or function is which applied to an object of inappropriate type.
  • ValueError: Raised when a function obtains an argument of the right type but inappropriate value.
  • IndexError: Raised when a sequences subscript is out of range.

How to Handle Exceptions Error?

Basic Exception Handling with try-except

The basic structure of exception handling in Python involves the use of try and except blocks. Here’s a simple example:

try:

    result = 10 / 0

except ZeroDivisionError:

    print(“You cannot divide by zero!”)

In this example, the codes within the try block efforts to perform a division by zero, which raises a ZeroDivisionError. The except block catches this exception and prints an error message.

Using Multiple Except Clauses

You can handle multiple exceptions by using multiple except clauses. This allows you to manage different types of errors in specific ways:

try:

    value = int(“not_a_number”)

except ValueError:

    print(“ValueError: Could not convert string to integer.”)

except TypeError:

    print(“TypeError: An unexpected type was used.”)

Here, the try block tries to convert a non-numeric string to an integer. The ValueError exception is caught, and a relevant message is printed. If a different type of error occurred, it would be caught by the TypeError clause.

The Finally Block

The finally block can be used to run code regardless of whether an exception as thrown. It is typically used for housekeeping tasks such as closing files and releasing resources.

try:

    file = open(‘example.txt’, ‘r’)

    # Perform file operations

finally:

    file.close()

    print(“File has been closed.”)

In this example, the finally block ensures that the file is closed regardless of whether an exception occurred. Learn all the Python techniques and Become a Python developer Expert. Enroll in our Python Online Training.

Raising Exceptions

You can also raise exceptions deliberately using the raise keyword. This is useful when you want to enforce certain conditions or indicate that an error has occurred:

def divide(a, b):

    if b == 0:

        raise ValueError(“Denominator cannot be zero.”)

    return a / b

try:

    result = divide(10, 0)

except ValueError as e:

    print(e)

Here, a ValueError is raised if the denominator is zero, and the exception message is printed.

Creating Custom Exceptions

In Python, you can develop custom exceptions by subclassing the built-in Exception class. This allows you to define your own error types:

class CustomError(Exception):

    def __init__(self, message):

        self.message = message

        super().__init__(self.message)

try:

    raise CustomError(“This is a custom error message.”)

except CustomError as e:

    print(e)

In this example, CustomError is a user-defined exception that is raised and handled in a try-except block.

Effective exception and error handling is essential for creating robust and reliable Python applications. By using try, except, finally, and raise, you can manage errors gracefully and ensure that your programs continue to run easily even when unexpected issues arise. Understanding how to handle different types of exceptions and create custom error messages will enhance your ability to build resilient software. By implementing these practices, you’ll be better equipped to tackle challenges and ensure a better experience for users of your Python applications. Looking for a career as a python developer? Enroll in this professional Programming Languages Institutes in Chennai and learn from experts about Important Programming Basics in Python, Loops, Control Statements, Functions, Modules and Packages in Python.

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