Python Inheritance

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Python Inheritance

Inheritance is a core concept in Python that allows one class to reuse the properties and behaviors of another class. It helps reduce code duplication and makes programs easier to manage.

• Base Class (Parent Class): The class whose features are inherited.
• Derived Class (Child Class): The class that receives properties and methods from another class.

Creating a Base Class

Any normal Python class can act as a base class.

Example

Create a base class named Employee with name and department attributes and a method to display details:

class Employee: def __init__(self, name, department): self.name = name self.department = department def show_details(self): print("Name:", self.name) print("Department:", self.department) # Create an object of Employee emp1 = Employee("Aarav", "IT") emp1.show_details()

Name: Aarav Department: IT

Creating a Derived Class

To create a child class, pass the base class name inside parentheses during class creation.

Example

Create a class Manager that inherits from the Employee class:

class Employee: def __init__(self, name, department): self.name = name self.department = department def show_details(self): print("Name:", self.name) print("Department:", self.department) class Manager(Employee): pass mgr1 = Manager("Neha", "HR") mgr1.show_details()

Name: Neha Department: HR

Note: Use the pass keyword when you don’t want to add any new properties or methods. Now, the Manager class can use everything from the Employee class.

Adding an __init__() Method to the Child Class

When you define an __init__() method inside the child class, it overrides the parent’s constructor.

Example

Add an __init__() method to the Manager class:

class Employee: def __init__(self, name, department): self.name = name self.department = department def show_details(self): print("Name:", self.name) print("Department:", self.department) class Manager(Employee): def __init__(self, name, department): Employee.__init__(self, name, department) mgr1 = Manager("Neha", "HR") mgr1.show_details()

Name: Neha Department: HR

Calling the parent’s __init__() ensures the inherited attributes are initialized correctly.

Using the super() Function

Python provides the super() function to make inheritance cleaner and more readable.

Example

Rewrite the previous constructor using super():

class Employee: def __init__(self, name, department): self.name = name self.department = department def show_details(self): print("Name:", self.name) print("Department:", self.department) class Manager(Employee): def __init__(self, name, department): super().__init__(name, department) mgr1 = Manager("Neha", "HR") mgr1.show_details()

Name: Neha Department: HR

Using super() removes the need to explicitly mention the parent class name.

Adding New Properties to the Child Class

A child class can have its own additional properties.

Example

Add a team_size property to the Manager class:

class Employee: def __init__(self, name, department): self.name = name self.department = department class Manager(Employee): def __init__(self, name, department, team_size): super().__init__(name, department) self.team_size = team_size mgr2 = Manager("Rohan", "Finance", 8) print("Team Size:", mgr2.team_size)

Team Size: 8

Adding New Methods to the Child Class

You can also define methods that exist only in the child class.

Example

Add a greet_team() method to the Manager class:

class Employee: def __init__(self, name, department): self.name = name self.department = department class Manager(Employee): def __init__(self, name, department, team_size): super().__init__(name, department) self.team_size = team_size def greet_team(self): print( "Hello, I am", self.name, "from", self.department, "department managing a team of", self.team_size, "members." ) mgr2 = Manager("Rohan", "Finance", 8) mgr2.greet_team()

Hello, I am Rohan from Finance department managing a team of 8 members.

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