What is Python Classes and Objects?

Published by Anshul Verma on

Table of Contents:-

  • Introduction to Class And Object in Python
  • What is a Python Class?
  • Define a class in Python
  • Advantages Of Classes In Python
  • Class Object
  • Methods in class
    • The Self
    • __init__ method
    • Class and Instance Variables
  • How to delete Python Class, Attribute or Object?

Introduction to Class And Object in Python

Python is an object-oriented programming language it is a way of computer programming using the idea of “Class and objects” to represent data and methods. It is also, an approach used for creating neat and reusable code rather than a redundant one. The Python program is split into self-contained objects or several mini-programs. Every Individual a special a part of the appliance having its own logic and data to communicate within themselves.

What is a Python Class?

A class in python is the blueprint from which specific objects are created. It lets you structure your software in a particular way. Here comes a question how? Classes allow us to logically group our data and function in a way that it is easy to reuse and a way to build upon if need to be. Consider the below image.

ClassesAndObjects - Python class - Edureka

In the first image (A), it represents a blueprint of a house that can be considered as Class. With the same blueprint, we can create several houses and these can be considered as Objects. Using a class, you can add consistency to your programs so that they can be used in a cleaner and efficient ways. The attributes are data members (class variables and instance variables) and methods which are accessed via dot notation(.)

We can think of a class as a sketch (Prototype) of the product. It contains height, Weight, Dimension, etc. best on this description of data we build the sketch of the product. As many products can be made from a product blueprint. We can create many objects from a class. An object is called the instance of a python class and the process of creating this object is called instantiation.

Define a class in Python

https://intellipaat.com/mediaFiles/2019/03/python10.png

To Create class use keyword ‘class’, Class have an attribute as variables. Class attribute always public can be accessed by using Dot( . ).

Example:- class.attribute

Example:- 

class car:

pass

In the above example, the class keyword indicates that you are creating a class followed by the name of the class (car in this case).

Example 2:- Create a class pass attribute into it and add a function into it to return a string.

Advantages Of Using Classes In Python

  • Classes provide an easy way of keeping the data members and methods together in one place which helps in keeping the program more organized.
  • Using classes also provides another functionality of this object-oriented programming paradigm, that is, inheritance.
  • Classes also help in overriding any standard operator.
  • Using classes provides the ability to reuse the code which makes the program more efficient.
  • Grouping related functions and keeping them in one place (inside a class) provides a clean structure to the code which increases the readability of the program.

Things to remember about a Python class

  • It is used to create custom types.
  • The class keyword is used to define a new class
  • It defines the structure and behaviour of objects
  • Conventionally a class name uses CamelCase

Class Object

Objects - python class - Edureka

An object is a collection of variable and function method that acts on the data and class is a blueprint for that object. The class object could be used to access different attributes. It is also used to create new object instances of the class. Creating an object is similar to a function call.

Example:- Create a class of details and call it by creating object of class :

Things to remember about an Object

  • Objects are real, have a state and occupy memory
  • Created/instantiated from a class specification and cannot exist without a class
  • There can be multiple objects of a class, each will have its own properties.

Methods in class

The Self

In the class, the method has an extra first parameter in the method definition. We don’t give the value for this parameter when we call the method, python provides it directly.

If we have a method that taken not an argument, then we still have to have one argument.

When we call a method of this object as an object.method(argument1,argument2), this is automatically converted by Python into Class.method(object, argument1,argument2)

__init__ method

The python __init__ method is similar to constructors in C++ and Java. A constructor is used to initialize the object state. Like methods, a constructor also contains a group of statements(i.e. instructions) that are executed at the time of when Object creation. It is run as soon as an object of a class is instantiated. The method is helpful to try and do any initialization you wish to do along with your object.

Example:-

Class and Instance Variables

Instance variables are from unique to each data instance and class variable re for attributes in class and the methods share all instances of the given class. Instance variables are the variables whose value is assigned inside into a constructor or method with self whereas class variables are variables whose value is assigned in the class.

Example 1:-  Defining instance variable using the constructor.

Program to show that the variables with a value assigned in the class declaration are class variables and variables inside methods and constructors are instance variables.

Output :

Example 2:–  Defining instance variable using the normal method in python.

Program to show that we can create instance variables inside methods

Things to remember about Instance methods

  • Called using objects
  • Must have self as the first parameter
  • (self is another python term. We can use self to access any data or other instance methods which resides in that class. These cannot be accessed without using self)

Things to remember about Initializer method

  • must be called __init__()
    (double underscore is used by python runtime)
  • The first parameter is self
  • If the initializer method is present, the constructor calls __init__()

How to Delete Python Class, Attribute, and Object?

You can delete an attribute, an object, or a class using the del keyword.

You can do the same for a specific attribute, object or a specific class.

Conclusion:-

In this blog, you will get knowledge about how to create classes and objects in python with different methods. And the example gives you a better understanding of the syntax to create class and object in python. I will be discussing OOP’s concept in my next blog….

Till then, Stay Safe, Stay Happy & Keep Coding…

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