Single inheritance in Python

In this tutorial, we'll explore the concept of Single inheritance in Python. Single inheritance allows us to define a new class that inherits properties and methods from a parent class. We'll cover how to define a subclass. By the end of this tutorial, you'll have a solid understanding of how to use Single inheritance in Python to create efficient and well-structured code.

What is single inheritance :

• Single inheritance is a type of inheritance where a sub-class inherits properties and methods from a single super-class.
• super-class is also known as the parent class and sub-class is also known as child class.
• It is the simplest form of inheritance and is used when there is only one parent class from which the child class needs to inherit.

Implementing single inheritance in python 

• To implement single inheritance in python, we specify the name of the parent class within parentheses while defining the child class.
• The syntax of implementing single inheritance in python is as follows :

class SubClass(SuperClass):
	# class-body
		
		

super() function

•  We can use the  super()  function in python to access members of the parent class.
• The  super()  function returns a temporary object of the super-class which allows the sub-class to call its methods.
• We can initialize the data members of child class in the constructor as we normally do.
• The data members of the parent class can be initialized from the child class by calling the  __init__()  function of the parent class through  super()  function.
• The syntax of calling parent class constructor from the child class is shown below. Here 
  •  arg_1, arg_2  are the values used to initialize the data members of the child class while
  •  arg_3, arg_4  are the values passed to parent-class to initialize its data members.

class SubClass(SuperClass):
    def __init__(self, arg_1, arg_2, arg_3, arg_4):
        self.var_1 = arg_1
        self.var_2 = arg_2
        super().__init__(arg_3, arg_4)
		
		
		

Code sample for single inheritance 

Below we have a full working example of single inheritance in python

class Vehicle:
    def __init__(self, make, model):
        self.make = make
        self.model = model


class Car(Vehicle):
    def __init__(self, make, model, utility, transmission):
        self.utility = utility
        self.transmission = transmission
        super().__init__(make, model)

    def show_details(self):
        print(f"The make of the Car is : {self.make}")
        print(f"The model of the Car is : {self.model}")
        print(f"The utility of the Car is : {self.utility}")
        print(f"The transmission of the Car is : {self.transmission}")


my_car = Car("Audi", 2023, "SUV", "Automatic")
my_car.show_details()


# Output
# The make of the Car is : Audi
# The model of the Car is : 2023
# The utility of the Car is : SUV
# The transmission of the Car is : Automatic

Overriding methods :

• Sub-class can override the methods of their super-class by defining a method with the same name.
• The sub-class method will be called instead of the super-class method when a method is called on an instance of the sub-class.
• Code Sample : 

class Vehicle:
    def __init__(self, make, model):
        self.make = make
        self.model = model

    def show_details(self):
        print(f"The make of the Vehicle  is : {self.make}")
        print(f"The model of the Vehicle is : {self.model}")
        print()


class Car(Vehicle):
    def __init__(self, make, model, utility, transmission):
        self.utility = utility
        self.transmission = transmission
        super().__init__(make, model)

    # Overriding method of the super class
    def show_details(self):
        print(f"The make of the Car is : {self.make}")
        print(f"The model of the Car is : {self.model}")
        print(f"The utility of the Car is : {self.utility}")
        print(f"The transmission of the Car is : {self.transmission}")
        print()


my_vehicle = Vehicle("BMW", 2022)
my_car = Car("Audi", 2023, "SUV", "Automatic")

# Calling show_details method of super class
my_vehicle.show_details()

# Calling show_details method of sub class
my_car.show_details()


# Output
# The make of the Vehicle  is : BMW
# The model of the Vehicle is : 2022

# The make of the Car is : Audi
# The model of the Car is : 2023
# The utility of the Car is : SUV
# The transmission of the Car is : Automatic

Accessing super-class methods :

• Sub-class can access the methods of their Super-class by using the  super()  function followed by the method name.
• Code Sample : 

class Vehicle:
    def __init__(self, make, model):
        self.make = make
        self.model = model

    def show_details(self):
        print(f"The make of the Vehicle  is : {self.make}")
        print(f"The model of the Vehicle is : {self.model}")
        print()


class Car(Vehicle):
    def __init__(self, make, model, utility, transmission):
        self.utility = utility
        self.transmission = transmission
        super().__init__(make, model)

    # Overriding method of the super class
    def show_details(self):
        
        # Calling show_details method of super class
        super().show_details()
        
        print(f"The utility of the Car is : {self.utility}")
        print(f"The transmission of the Car is : {self.transmission}")
        print()


my_car = Car("Audi", 2023, "SUV", "Automatic")
my_car.show_details()


# Output:
# The make of the Vehicle  is : Audi
# The model of the Vehicle is : 2023

# The utility of the Car is : SUV
# The transmission of the Car is : Automatic