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Class,Object and Members
In this tutorial we will learn Class, Object and Members in Python.
In Python, classes are used to create objects, which are instances of those classes. Classes serve as blueprints or templates for creating objects with similar characteristics and behaviors. Each object created from a class is called an instance or an object of that class.
A class defines the properties (also known as attributes) and behaviors (also known as methods) that objects of that class will have. Attributes are variables that store data, while methods are functions that define the behavior of the class.
Here’s an example of a simple class definition in Python:
class Car:
def __init__(self, make, model, year):
self.make = make
self.model = model
self.year = year
def start_engine(self):
print("The engine has started.")
def drive(self):
print("The car is being driven.")
def stop_engine(self):
print("The engine has stopped.")In the above example, Car is the class, and make, model, and year are its attributes. The __init__ method is a special method called the constructor, which is executed when an instance of the class is created. It initializes the attributes of the object using the values passed as arguments.
The start_engine, drive, and stop_engine methods are behaviors associated with the Car class. They define the actions that objects of the Car class can perform.
To create an instance of the Car class, you can do the following:
my_car = Car("Toyota", "Camry", 2022)Here, my_car is an object of the Car class. It has the attributes make (set to “Toyota”), model (set to “Camry”), and year (set to 2022). You can access the attributes and call the methods of the object using dot notation, like this:
print(my_car.make) # Output: Toyota
print(my_car.model) # Output: Camry
print(my_car.year) # Output: 2022
my_car.start_engine() # Output: The engine has started.
my_car.drive() # Output: The car is being driven.
my_car.stop_engine() # Output: The engine has stopped.
In summary, classes define the structure and behavior of objects, while objects are instances of those classes. Members refer to the attributes and methods associated with a class or an object. Attributes store data, and methods define the behaviors or actions that can be performed by the class or object.
Python OOPs Concepts
Python supports object-oriented programming (OOP) concepts. Here are the main concepts in Python OOP:
1. Classes and Objects: A class is a blueprint for creating objects, while an object is an instance of a class. Classes define the properties (attributes) and behaviors (methods) that objects of that class can have.
2. Encapsulation: Encapsulation is the process of bundling data and methods within a class, hiding the internal details and protecting the data from direct manipulation. It is achieved by using access modifiers like public, private, and protected.
3. Inheritance: Inheritance allows a class to inherit properties and methods from another class. The class being inherited from is called the base class or superclass, and the class inheriting from it is called the derived class or subclass. The derived class can extend or override the functionality of the base class.
4. Polymorphism: Polymorphism allows objects of different classes to be treated as objects of a common superclass. It enables methods with the same name to be called on different objects, and the appropriate method is executed based on the object’s type. Polymorphism can be achieved through method overriding and method overloading.
5. Method Overriding: Method overriding occurs when a derived class defines a method with the same name as a method in its superclass. The derived class’s method overrides the implementation of the base class method, allowing the derived class to provide its own implementation.
6. Method Overloading: Method overloading enables a class to have multiple methods with the same name but different parameters. Python does not support method overloading directly, but you can achieve similar behavior using default argument values or variable-length argument lists.
7. Abstraction: Abstraction refers to the process of hiding complex implementation details and providing a simplified interface. It allows the user to interact with the objects without needing to know the underlying complexity. Abstract classes and interfaces are used to achieve abstraction in Python.
8. Composition: Composition is a form of association where one class contains an instance of another class as a member. It allows creating complex objects by combining simpler objects. Composition is often used when the relationship between classes is not a “is-a” relationship (as in inheritance) but rather a “has-a” relationship.
These concepts form the foundation of object-oriented programming in Python. By utilizing these concepts, you can create modular, reusable, and maintainable code that models real-world entities effectively.