Python Class and Object-Oriented Programming

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 attributes (data) and methods (functions)

Class Syntax

• Define a class using the class keyword
• Class name should start with a capital letter (e.g., Dog)
• Class definition should include the __init__ method (initializer)

Attributes

• Instance variables (attributes) are defined inside the __init__ method
• Access attributes using dot notation (e.g., my_dog.name)

Methods

• Instance methods are functions defined inside the class
• Methods operate on the object's attributes
• Use self as the first parameter to refer to the object

Inheritance

• Inheritance allows one class to build upon another class
• The child class inherits attributes and methods from the parent class
• Use the super() function to access the parent class

Polymorphism

• Polymorphism is the ability of an object to take on multiple forms
• In Python, polymorphism is achieved through method overriding
• Method overriding allows a child class to provide a different implementation of a method already defined in the parent class

Encapsulation

• Encapsulation is the concept of hiding implementation details from the outside world
• In Python, encapsulation is achieved through the use of private variables (prefixed with double underscore __)
• Use getter and setter methods to access and modify private variables

Abstraction

• Abstraction is the concept of showing only essential features to the outside world
• In Python, abstraction is achieved through the use of abstract classes and interfaces
• Abstract classes provide a blueprint for other classes to follow

Special Methods

• Special methods are used to override built-in Python operators and functions
• Examples: __str__, __repr__, __add__, __len__
• Use special methods to create a more intuitive and user-friendly interface for your objects

Object-Oriented Programming in Python

Classes and Objects

• A class serves as a blueprint for creating objects, which are instances of the class.
• Classes define two essential components: attributes (data) and methods (functions).

Class Syntax

• The class keyword is used to define a class.
• Class names should start with a capital letter, following the convention (e.g., Dog).
• The __init__ method, also known as the initializer, must be included in the class definition.

Attributes

• Instance variables, also known as attributes, are defined inside the __init__ method.
• Attributes can be accessed using dot notation, such as my_dog.name.

Methods

• Instance methods are functions defined inside the class, operating on the object's attributes.
• The self parameter is used to refer to the object, and it should be the first parameter in method definitions.

Inheritance

• Inheritance allows a child class to build upon a parent class, inheriting its attributes and methods.
• The super() function is used to access the parent class.

Polymorphism

• Polymorphism enables objects to take on multiple forms, achieved through method overriding in Python.
• Method overriding allows a child class to provide a different implementation of a method already defined in the parent class.

Encapsulation

• Encapsulation is the concept of hiding implementation details from the outside world.
• In Python, encapsulation is achieved using private variables, prefixed with double underscore __.
• Getter and setter methods are used to access and modify private variables.

Abstraction

• Abstraction is the concept of showing only essential features to the outside world.
• In Python, abstraction is achieved using abstract classes and interfaces.
• Abstract classes provide a blueprint for other classes to follow.

Special Methods

• Special methods are used to override built-in Python operators and functions, such as __str__, __repr__, __add__, and __len__.
• These methods enable the creation of a more intuitive and user-friendly interface for objects.

Object-Oriented Programming (OOP) in Python

Classes and Objects

• A class is a blueprint for creating objects, defining their attributes and methods.
• An object is an instance of a class, having its own set of attributes and methods.
• Classes are defined using the class keyword in Python.

Class Components

Attributes

• Attributes (or data members) are the data associated with an object.
• Attributes are defined inside the __init__ method in Python.
• Attributes can be accessed and modified using dot notation (e.g., object.attribute).

Methods

• Methods are functions that belong to a class.
• Methods are used to perform actions on an object's attributes.
• Methods are defined inside the class definition in Python.
• Methods can take arguments, including the self parameter, which refers to the object itself.

OOP Concepts

Inheritance

• Inheritance is a mechanism where a new class (subclass) inherits attributes and methods from an existing class (superclass).
• Inheritance is implemented using the class keyword followed by the superclass in parentheses in Python.

Polymorphism

• Polymorphism is the ability of an object to take on multiple forms.
• Polymorphism is achieved through method overriding in Python, where a subclass provides a different implementation of a method from its superclass.

Encapsulation

• Encapsulation is the concept of hiding an object's internal state and behavior from the outside world.
• Encapsulation is achieved through the use of private attributes (prefixed with double underscore __) and public methods in Python.

Abstraction

• Abstraction is the concept of showing only necessary information to the outside world while hiding implementation details.
• Abstraction is achieved through the use of abstract classes and interfaces in Python.

Special Methods

• Special methods (or magic methods) are used to override the behavior of built-in operators and functions.
• Examples of special methods include __init__, __str__, __add__, etc.