Tamilnadu Samacheer Kalvi 12th Computer Science Notes Chapter 10 Python Classes and Objects Notes

Class:

  • Classes and Objects are the key features of Object Oriented Programming.
  • A class is a way of binding data members and member function together.
  • Class is the main building block in Python.
  • Class is a template for the object.

Instantiation:
This process of creating object is called as
“Class Instantiation”.

Syntax:
Object_name = class_name()

Constructor in Python:

  • In Python, there is a special function called “init” which act as a Constructor.
  • It must begin and end with double underscore.
  • This function will act as an ordinary function; but only difference is, it is executed automatically when the object is created.
  • This constructor function can be defined with or without arguments.
  • This method is used to initialize the class variables.

General format of _init_ method(Constructor function):
def _init_(self, [args ]):
< statements >

Destructor:

  • Destructor is a special method gets executed automatically when an object exit from the scope.
  • It is just opposite to constructor.
  • In Python, _del_ ( ) method is used as destructor.

Class members:

  • Variables defined inside a class are called as “Class Variable” and Functions defined inside are called as “Methods’:
  • Class variable and methods are together known as members of the class.
  • The class members should be accessed through objects or instance of class.

Defining class members:
Any class member (class variable or method (function)) can be defined and accessed by using object with a dot ( . ) operator.

Syntax:
Object_name .class_member

public and private data members of python class:

  • The variables which are defined inside the class is public by default. These variables can be accessed anywhere in the program using dot operator.
  • A variable prefixed with double underscore becomes private in nature. These variables can be accessed only within the class.

Object:

  • Object is a collection of data and function that act on those data.
  • Class is a template for the object.
  • According to the concept of Object Oriented Programming, objects are also called as instances of a class or class variable.
  • In Python, everything is an object.

Creating Objects:

  • Once a class is created, next we should create an object or instance of that class.
  • The process of creating object is called as “Class Instantiation”.

Syntax:
Object_name = class_name()

Accessing Class Members:
Any class member ie. class variable or method (function) can be accessed by using object with a dot (.) operator.

Syntax:
Object_name. class_member

Samacheer Kalvi 12th Computer Science Notes

Leave a Reply

Your email address will not be published. Required fields are marked *