Python OOP: Classes and Objects

Object-Oriented Programming in Python

Classes and Objects

• A class is a blueprint for creating objects
• An object is an instance of a class
• Classes define properties (data) and behaviors (methods)

Class Syntax

• Define a class using the class keyword
• Class names should follow the PascalCase convention (e.g., MyClass)
• Indentation is used to define the class body

class MyClass:
    # class body

Constructors (__init__ method)

• The __init__ method is a special method that is called when an object is created
• It is used to initialize object attributes
• The self parameter refers to the current object being created

class MyClass:
    def __init__(self, attr1, attr2):
        self.attr1 = attr1
        self.attr2 = attr2

Attributes and Methods

• Attributes are data members of a class (e.g., attr1, attr2)
• Methods are functions that belong to a class (e.g., my_method)
• Attributes and methods can be accessed using dot notation (e.g., my_object.attr1, my_object.my_method())

Inheritance

• Inheritance is a mechanism that allows one class to inherit properties and behaviors from another class
• The child class inherits from the parent class using the class ChildClass(ParentClass): syntax
• The child class can override or extend the parent class's attributes and methods

class ParentClass:
    def my_method(self):
        print("Parent method")

class ChildClass(ParentClass):
    def my_method(self):
        print("Child method")

Encapsulation and Abstraction

• Encapsulation is the concept of hiding internal implementation details from the outside world
• Abstraction is the concept of showing only necessary information to the outside world
• Python supports encapsulation and abstraction through the use of private attributes (prefixed with double underscore __) and abstract methods

Polymorphism

• Polymorphism is the ability of an object to take on multiple forms
• Python supports polymorphism through method overriding and operator overloading

class Animal:
    def sound(self):
        print("Animal makes a sound")

class Dog(Animal):
    def sound(self):
        print("Dog barks")

Classes and Objects

• A class is a blueprint for creating objects, defining properties (data) and behaviors (methods)
• An object is an instance of a class, with its own set of attributes and methods

Class Syntax and Naming

• Define a class using the class keyword, following the PascalCase convention (e.g., MyClass)
• Class body is defined using indentation

Constructors (__init__ method)

• __init__ method is called when an object is created, used to initialize object attributes
• The self parameter refers to the current object being created
• __init__ method is used to set initial values for object attributes

Attributes and Methods

• Attributes are data members of a class (e.g., attr1, attr2)
• Methods are functions belonging to a class (e.g., my_method())
• Attributes and methods can be accessed using dot notation (e.g., my_object.attr1, my_object.my_method())

Inheritance

• Inheritance allows a child class to inherit properties and behaviors from a parent class
• Child class inherits from parent class using class ChildClass(ParentClass): syntax
• Child class can override or extend parent class's attributes and methods

Encapsulation and Abstraction

• Encapsulation hides internal implementation details from the outside world
• Abstraction shows only necessary information to the outside world
• Python supports encapsulation and abstraction through private attributes (prefixed with double underscore __) and abstract methods

Polymorphism

• Polymorphism allows an object to take on multiple forms
• Python supports polymorphism through method overriding and operator overloading
• Method overriding allows a child class to provide a specific implementation for a method already defined in its parent class