Python Class and Objects Example

Python Class and Objects example:-

1) Write code sample.py:-

# Sample class with init method

class Person:

    # init method or constructor

    def __init__(self, name):

        self.name = name

    # Sample Method

    def say_hi(self):

        print('Hello, my name is', self.name)

p = Person('Om')

p.say_hi()

Output:-

Hello, my name is Om

2) Class and Instance Variables

# Python3 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.

# Class for Dog

class Dog:

    # Class Variable

    animal = 'dog'

    # The init method or constructor

    def __init__(self, breed, color):

        # Instance Variable

        self.breed = breed

        self.color = color

# Objects of Dog class

Rodger = Dog("Pug", "brown")

Buzo = Dog("Bulldog", "black")

print('Rodger details:')

print('Rodger is a', Rodger.animal)

print('Breed: ', Rodger.breed)

print('Color: ', Rodger.color)

print('\nBuzo details:')

print('Buzo is a', Buzo.animal)

print('Breed: ', Buzo.breed)

print('Color: ', Buzo.color)

# Class variables can be accessed using class

# name also

print("\nAccessing class variable using class name")

print(Dog.animal)

Output:-

Rodger details:

Rodger is a dog

Breed: Pug

Color: brown

Buzo details:

Buzo is a dog

Breed: Bulldog

Color: black

Accessing class variable using class name

dog

3)Defining instance variables using the normal method.

# Python3 program to show that we can create

# instance variables inside methods

# Class for Dog

class Dog:

    # Class Variable

    animal = 'dog'

    # The init method or constructor

    def __init__(self, breed):

        # Instance Variable

        self.breed = breed

    # Adds an instance variable

    def setColor(self, color):

        self.color = color

    # Retrieves instance variable

    def getColor(self):

        return self.color

# Driver Code

Rodger = Dog("pug")

Rodger.setColor("brown")

print(Rodger.getColor())

Output:-

brown

4)Inheritance example :-

# A Python program to demonstrate inheritance

# Base or Super class. Note object in bracket.

# (Generally, object is made ancestor of all classes)

# In Python 3.x "class Person" is

# equivalent to "class Person(object)"

class Person(object):

    # Constructor

    def __init__(self, name):

        self.name = name

    # To get name

    def getName(self):

        return self.name

# Inherited or Subclass (Note Person in bracket)

class Employee(Person):

    # Here we return true

    def isEmployee(self):

        return True

# Driver code

emp = Person("om1") # An Object of Person

print(emp.getName())

emp = Employee("om2") # An Object of Employee

print(emp.getName(), emp.isEmployee())

Output:-

om1

om2 True

5)Subclassing (Calling constructor of parent class)

# Python code to demonstrate how parent constructors

# are called.

# parent class

class Person(object):

    # __init__ is known as the constructor

    def __init__(self, name, idnumber):

        self.name = name

        self.idnumber = idnumber

    def display(self):

        print(self.name)

        print(self.idnumber)

# child class

class Employee(Person):

    def __init__(self, name, idnumber, salary, post):

        self.salary = salary

        self.post = post

        # invoking the __init__ of the parent class

        Person.__init__(self, name, idnumber)

# creation of an object variable or an instance

a = Employee('Rahul', 886012, 200000, "Intern")

# calling a function of the class Person using its instance

a.display()

Output:-

Rahul

886012

Django

Python Class and Objects Example