How To Properly Define And Use Python Class – Easy Example Code

In this article, we’ll learn what Python class is and how to properly define and use it in code.

We’ll be using multiple practical Python code examples with step by step explanation to better understand how Python class works.

After reading this article, you’ll have a practical knowledge of how to use Python classes.

So without wasting anymore time, let’s just throw ourselves into its practical implementation.

What is Python Class?

As you may already know that Python is an object-oriented programming language. It possess the concept of objects and classes.

An object can be defined as a collection of data like variables and methods (functions) that act on that data. Similarly,  a class works as a blueprint for object.

There can be many objects of the same class. Class has attributes that the object can use to perform actions. These attributes can be a function, variable etc.

Let’s now understand the concept of Python class using practical examples. But let’s first understand its syntax.

Syntax of Python Class

class ClassName:
      // body of class

It starts with the class keyword.

Then comes name of the class and this line ends with a colon(:).

Use indentation to specify the body of class. You can specify variables or functions in it.

Implementing Python Class (Multiple Examples)

Below examples will give you a proper idea of how to define and use Python class.

Example 1: Define a Class

class ClassName:
    """This is a doc string"""

A class is created. We’ve also used a doc string in it. Doc string can be used as a first statement in the class. It specifies all the details about that class.

Use triple quotes to write this doc string in multiple line. Although, doc string not mandatory but specifying it is a good practice.

Example 2: Create Variable in Class

class ClassName:
    value='I am inside class'

This is how you can create a variable inside a class. Let’s now see how to fetch its value.

When a new class is created, then an object with the same name is also created. It can be used to fetch data from that class and also to create new objects of the same class.

Let’s now fetch the data of variable using this object.

class ClassName:
    value='I am inside class'
print(ClassName.value)

Output

I am inside class

Example 3: Create an Object of Class

obj=className

This is how you can create an object of some specific class. You can specify any name to that object.

Let’s now see how to fetch the above created variable data using a newly created object. See below code:

class className:
    value='I am inside class'

obj=className    // new object created
print(obj.value) // it will print the data of value variable of class

Output

I am inside class

You can see that we’ve fetched the data of variable using( objectName.classVariableName ).

Example 4: Create Function in Class

class ClassName:
    def classFun():    // function created
      print('I am inside function of a class')

objFun=ClassName     
objFun.classFun()     // function called using object of the same class

Output

I am inside function of a class

class ClassName:
    def classFun(self): // self will store the object
    print('My name is '+self.name)

objFun=ClassName()
objFun.name='Yasir'    // create a variable attribute of that class and initialize it
objFun.classFun()      // My name is Yasir

My name is Yasir

class ClassName:
var=0
  def __init__(self,val=5):   // constructor
    var=val
    print(var)

objFun=ClassName()

5