Python :Class & Objects

Python(3.6) is an object oriented programming language,everything in Python is an object.Unlike procedure oriented programming, where the main emphasis is on functions, object oriented programming stress on objects.

Object is simply a collection of data (variables) and methods (functions) that act on those data.

Class variable − A variable that is shared by all instances of a class. Class variables are defined within a class but outside any of the class's methods. Class variables are not used as frequently as instance variables are.

Data member − A class variable or instance variable that holds data associated with a class and its objects.

Instance variable − A variable that is defined inside a method and belongs only to the current instance of a class.

Instance − An individual object of a certain class. An object obj that belongs to a class Circle, for example, is an instance of the class Circle.

Instantiation − The creation of an instance of a class.

create class:classes are defined by the "Class" keyword

class classname():

variables;

to declare functions in python using "def" keyword followed by function name.

def functioname():

# declare varables and functions in class below sample example

create instance of class: objectname=classname()
you can call mehtod/s using objectname.methodname().

The Constructor Method:

The constructor method is used to initialize data. It is run as soon as an object of a class is instantiated. Also known as the __init__ method, it will be the first definition of a class and looks like this: