All about python Inheritance.python codingdf

Python Inheritance (BCAC403)
Inheritance is an important aspect of the object-oriented
paradigm. Inheritance provides code reusability to the program
because we can use an existing class to create a new class.
In inheritance, the child class acquires the properties and can
access all the data members and functions defined in the parent
class.
A child class can also provide its specific implementation to the
functions of the parent class.

In python, a derived class can inherit base class by just mentioning the
base in the bracket after the derived class name. Consider the following
syntax to inherit a base class into the derived class.
Syntax:
Class BaseClass:
{Body}
Class DerivedClass(BaseClass):
{Body}

Benefits of Inheritance
It represents real-world relationships well.
It provides the reusability of a code. We don’t have to write the
same code again and again.
It is transitive in nature, which means that if class B inherits
from another class A, then all the subclasses of B would
automatically inherit from class A.
Inheritance offers a simple, understandable model structure.
Less development and maintenance expenses result from an
inheritance.

Note:
The process of inheriting the properties of the parent class into a child class is
called inheritance. The main purpose of inheritance is the reusability of code
because we can use the existing class to create a new class instead of creating
it from scratch.
In inheritance, the child class acquires all the data members, properties, and
functions from the parent class. Also, a child class can also provide its specific
implementation to the methods of the parent class.
For example: In the real world, Car is a sub-class of a Vehicle class. We can
create a Car by inheriting the properties of a Vehicle such as Wheels, Colors,
Fuel tank, engine, and add extra properties in Car as required.
Syntax:
class BaseClass:
//Body of base class
{Body}
class DerivedClass(BaseClass):
//Body of derived class
{Body}

Types of Inheritance in Python
1.Single inheritance
2.Multiple Inheritance
3.Multilevel inheritance
4.Hierarchical Inheritance
5.Hybrid Inheritance

1.Single Inheritance:
Single inheritance enables a derived class to inherit properties
from a single parent class, thus enabling code reusability and the
addition of new features to existing code.

Example
# Base class
class Vehicle:
def Vehicle_info(self):
print('Inside Vehicle class')
# Child class
class Car(Vehicle):
def car_info(self):
print('Inside Car class')
# Create object of Car
car = Car()
# access Vehicle's info using car object
car.Vehicle_info()
car.car_info()
Output:
Inside Vehicle class
Inside Car class

Example
class Animal:
def speak(self):
print("Animal Speaking")
#child class Dog inherits the base class Animal
class Dog(Animal):
def bark(self):
print("dog barking")
d = Dog()
d.bark()
d.speak()
Output:
dog barking
Animal Speaking

2.Multiple Inheritance:
When a class can be derived from more than one base class this
type of inheritance is called multiple inheritances. In multiple
inheritances, all the features of the base classes are inherited into
the derived class.

Example
# Parent class 1
class Person:
def person_info(self, name, age):
print('Inside Person class')
print('Name:', name, 'Age:', age)
# Parent class 2
class Company:
def company_info(self, company_name, location):
print('Inside Company class')
print('Name:', company_name, 'location:', location)
# Child class
class Employee(Person, Company):
def Employee_info(self, salary, skill):
print('Inside Employee class')
print('Salary:', salary, 'Skill:', skill)
# Create object of Employee
emp = Employee()
# access data
emp.person_info('Jessa‘, 28)
emp.company_info('Google', 'Atlanta')
emp.Employee_info(12000, 'Machine Learning')

Output:
Inside Person class
Name: Jessa Age: 28
Inside Company class
Name: Google location: Atlanta
Inside Employee class
Salary: 12000 Skill: Machine Learning

Example:
class Calculation1:
def Summation(self,a,b):
return a+b;
class Calculation2:
def Multiplication(self,a,b):
return a*b;
class Derived(Calculation1,Calculation2):
def Divide(self,a,b):
return a/b;
d = Derived()
print(d.Summation(10,20))
print(d.Multiplication(10,20))
print(d.Divide(10,20))
Output:
30
200
0.5

Multilevel Inheritance
In multilevel inheritance, features of the base class and the derived
class are further inherited into the new derived class. This is similar
to a relationship representing a child and a grandfather.

Example
# Base class
class Vehicle:
def Vehicle_info(self):
print('Inside Vehicle class')
# Child class
class Car(Vehicle):
def car_info(self):
print('Inside Car class')
# Child class
class SportsCar(Car):
def sports_car_info(self):
print('Inside SportsCar class')
# Create object of SportsCar
s_car = SportsCar()
# access Vehicle's and Car info using SportsCar object
s_car.Vehicle_info()
s_car.car_info()
s_car.sports_car_info()

Output:
Inside Car class
Inside SportsCar class

Example
class Animal:
def speak(self):
print("Animal Speaking")
#The child class Dog inherits the base class Animal
class Dog(Animal):
def bark(self):
print("dog barking")
#The child class Dogchild inherits another child class Dog
class DogChild(Dog):
def eat(self):
print("Eating bread...")
d = DogChild()
d.bark()
d.speak()
d.eat()
Output:
dog barking
Animal Speaking
Eating bread...

Hierarchical Inheritance
When more than one derived class are created from a single base
this type of inheritance is called hierarchical inheritance. In this
program, we have a parent (base) class and two child (derived)
classes.

Example
Let’s create ‘Vehicle’ as a parent class and two child class ‘Car’ and ‘Truck’
as a parent class.
class Vehicle:
def info(self):
print("This is Vehicle")
class Car(Vehicle):
def car_info(self, name):
print("Car name is:", name)
class Truck(Vehicle):
def truck_info(self, name):
print("Truck name is:", name)
obj1 = Car()
obj1.info()
obj1.car_info('BMW')
obj2 = Truck()
obj2.info()
obj2.truck_info('Ford')

Output:
This is Vehicle
Car name is: BMW
This is Vehicle
Truck name is: Ford

Hybrid Inheritance
Inheritance consisting of multiple types of inheritance is called
hybrid inheritance.

Example:
class Vehicle:
def vehicle_info(self):
print("Inside Vehicle class")
class Car(Vehicle):
def car_info(self):
print("Inside Car class")
class Truck(Vehicle):
def truck_info(self):
print("Inside Truck class")
# Sports Car can inherits properties of Vehicle and Car
class SportsCar(Car, Vehicle):
def sports_car_info(self):
print("Inside SportsCar class")
# create object
s_car = SportsCar()
s_car.vehicle_info()
s_car.car_info()
s_car.sports_car_info()

Output :
Inside Car class
Inside SportsCar class
Executed in: 0.01 sec(s)
Memory: 4188 kilobyte(s)

Python super() function
When a class inherits all properties and behavior from the parent
class is called inheritance. In such a case, the inherited class is a
subclass and the latter class is the parent class.
In child class, we can refer to parent class by using
the super() function. The super function returns a temporary
object of the parent class that allows us to call a parent class
method inside a child class method.

Benefits of using the super() function.
We are not required to remember or specify the
parent class name to access its methods.
We can use the super() function in both single and multiple
inheritances.
The super() function support code reusability as there is no
need to write the entire function

Example:
class Company:
def company_name(self):
return 'Google'
class Employee(Company):
def info(self):
# Calling the superclass method using super()function
c_name = super().company_name()
print("Jessa works at", c_name)
# Creating object of child class
emp = Employee()
emp.info()
Output:
Jessa works at Google

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