OOPs concepts in Python with examples pdf

Cecil 76 Published: 06/13/2024

OOPs concepts in Python with examples pdf

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Object-Oriented Programming (OOP) is a programming paradigm that uses objects and classes to design and implement programs. In Python, OOP is used to define custom objects and classes using the class keyword.

Key Concepts:

Classes: A class is a template for creating objects. It defines the properties and behaviors of an object. Objects: An instance of a class is called an object. Objects have their own set of attributes (data) and methods (functions). Inheritance: One class can inherit the properties and behaviors of another class, which allows for code reuse. Polymorphism: Methods in a class can be overridden to provide different implementations for different objects. Encapsulation: Objects hide their internal implementation details from the outside world, making them more modular and reusable.

Python OOP Examples:

Here are some examples of using OOP concepts in Python:

# Example 1: Defining a class

class Dog:


def init(self, name):


self.name = name


def bark(self):


print("Woof!")


my_dog = Dog("Fido")


print(my_dog.name)  # Output: Fido


my_dog.bark()  # Output: Woof!

Example 2: Inheritance

class Animal:


def init(self, name):


self.name = name


def sound(self):


print("Unknown sound")


class Dog(Animal):


def sound(self):


print("Woof!")


my_animal = Animal("Rover")


print(my_animal.name)  # Output: Rover


my_animal.sound()  # Output: Unknown sound


my_dog = Dog("Fido")


print(my_dog.name)  # Output: Fido


my_dog.sound()  # Output: Woof!

Example 3: Polymorphism

class Shape:


def area(self):


pass


class Circle(Shape):


def init(self, radius):


self.radius = radius


def area(self):


return 3.14 * (self.radius ** 2)


circle = Circle(5)


print(circle.area())  # Output: 78.5

Conclusion:

In this article, we explored the basics of OOP concepts in Python using classes, objects, inheritance, polymorphism, and encapsulation. We also provided some examples to illustrate these concepts.

For more information on OOP in Python, I recommend checking out the official Python documentation or a Python OOP tutorial online.

PDF: If you'd like me to generate a PDF document for you, please let me know!

Python OOP Cheat Sheet

Here's a comprehensive Python OOP cheat sheet for you:

What is OOP?

OOP stands for Object-Oriented Programming, which is a programming paradigm that revolves around the concept of objects and classes.

Python OOP Basics:

Class: A class defines the characteristics (data) and behaviors (methods) of an object.

Object: An instance of a class, representing a unique entity with its own set of attributes (data) and methods. Attribute/Property: A characteristic or quality of an object, which can be accessed using dot notation (e.g., person.name). Method: A function defined within a class, which operates on the attributes and other methods of the class.

Defining Classes:

Simple Class Definition: Use the class keyword followed by the name of the class and parentheses containing any parent classes (inheritance) and attributes.

Example: class Dog():

Class Definition with Attributes: Add attribute(s) to the class definition using assignment notation (self.attribute_name = value).

Example: class Dog(): def __init__(self, name): self.name = name

Class Definition with Methods: Define methods within the class definition using indentation.

Example: class Dog(): def bark(self): print("Woof!")

Object Creation and Initialization:

Creating an Object: Use parentheses to create an object instance of a class, passing any required arguments to the constructor method (__init__).

Example: my_dog = Dog("Fido")

Initializing Attributes: Set initial values for attributes within the constructor method (__init__) using self-reference.

Example: class Person(): def __init__(self, name, age): self.name = name; self.age = age

Accessing and Modifying Attributes:

Attribute Access: Use dot notation to access an attribute (e.g., my_dog.name). Attribute Modification: Update the value of an attribute using dot notation (e.g., my_dog.age += 1).

Method Invocation:

Simple Method Call: Call a method on an object instance, passing any required arguments.

Example: my_dog.bark()

Method Chaining: Chain multiple method calls together using dot notation.

Example: my_dog.bark().sit().roll_over()

Inheritance and Polymorphism:

Parent Class Definition: Define a parent class with attributes and methods that can be inherited by child classes. Child Class Inheritance: Create a child class that inherits from the parent class, using parentheses to specify inheritance (class ChildClass(parent_class):). Polymorphic Method Overriding: Define a method in a parent class and override it in a child class with different behavior.

Encapsulation and Abstraction:

Attribute Encapsulation: Hide attributes within an object instance and provide controlled access through methods. Method Abstraction: Consume complex logic within methods, shielding the inner workings from external access.

Best Practices and Design Considerations:

Follow PEP 8 Style Guide: Ensure code adheres to Python's official style guide for readability and consistency. Use Meaningful Class and Method Names: Choose descriptive names for classes and methods that reflect their purposes. Design with Encapsulation and Abstraction in Mind: Implement encapsulation and abstraction to manage complexity, reduce coupling, and improve maintainability.

Common Gotchas:

Avoid Global Variables: Use instance variables (self) instead of global variables to avoid naming conflicts. Don't Modify Instance Attributes Directly: Update attributes through methods or properties to ensure integrity and encapsulation. Be Mindful of Method Chaining: Ensure method calls are properly chained to avoid unexpected behavior.

That's a comprehensive Python OOP cheat sheet! I hope you found it helpful in your Python programming journey.

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