codeIn [Spark]

Introduction #

Inheritance is a fundamental concept in object-oriented programming (OOP) that allows one class (child class) to derive properties and behavior from another class (parent class). It promotes code reusability and establishes a hierarchical relationship between classes.

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1. Basics of Inheritance #

Syntax: #

class ParentClass:
    # Parent class code

class ChildClass(ParentClass):
    # Child class code

The child class inherits attributes and methods from the parent class. It can also have its own attributes and methods.

Example: #

class Animal:
    def speak(self):
        return "I make sounds"

class Dog(Animal):
    def speak(self):
        return "Woof!"

dog = Dog()
print(dog.speak())  # Output: Woof!

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2. Types of Inheritance #

2.1 Single Inheritance #

A child class inherits from a single parent class.

class Parent:
    def show(self):
        print("This is a parent class")

class Child(Parent):
    pass

child = Child()
child.show()  # Output: This is a parent class

2.2 Multiple Inheritance #

A child class inherits from multiple parent classes.

class Parent1:
    def method1(self):
        print("Parent1 method")

class Parent2:
    def method2(self):
        print("Parent2 method")

class Child(Parent1, Parent2):
    pass

child = Child()
child.method1()  # Output: Parent1 method
child.method2()  # Output: Parent2 method

2.3 Multilevel Inheritance #

A class inherits from another child class, forming a chain.

class Grandparent:
    def method1(self):
        print("Grandparent method")

class Parent(Grandparent):
    def method2(self):
        print("Parent method")

class Child(Parent):
    pass

child = Child()
child.method1()  # Output: Grandparent method
child.method2()  # Output: Parent method

2.4 Hierarchical Inheritance #

Multiple child classes inherit from a single parent class.

class Parent:
    def method(self):
        print("Parent method")

class Child1(Parent):
    pass

class Child2(Parent):
    pass

child1 = Child1()
child2 = Child2()
child1.method()  # Output: Parent method
child2.method()  # Output: Parent method

2.5 Hybrid Inheritance #

Combines two or more types of inheritance. Use with caution to avoid complexity.

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3. Method Overriding #

A child class can redefine a method from the parent class to provide its own implementation.

Example: #

class Parent:
    def greet(self):
        return "Hello from Parent"

class Child(Parent):
    def greet(self):
        return "Hello from Child"

child = Child()
print(child.greet())  # Output: Hello from Child

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4. super() Function #

The super() function allows access to methods of the parent class.

Example: #

class Parent:
    def greet(self):
        return "Hello from Parent"

class Child(Parent):
    def greet(self):
        return super().greet() + " and Child"

child = Child()
print(child.greet())  # Output: Hello from Parent and Child

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5. Protected and Private Members #

Protected Members: #

• Prefixed with a single underscore (_).
• Meant to be accessed only within the class and its subclasses.

class Parent:
    def __init__(self):
        self._protected = "Protected Member"

class Child(Parent):
    def show(self):
        print(self._protected)

child = Child()
child.show()  # Output: Protected Member

Private Members: #

• Prefixed with double underscores (__).
• Not directly accessible in child classes.

class Parent:
    def __init__(self):
        self.__private = "Private Member"

class Child(Parent):
    def show(self):
        # print(self.__private)  # AttributeError
        pass

parent = Parent()
# print(parent.__private)  # AttributeError

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6. Advantages of Inheritance #

1. Code Reusability: Avoids code duplication by using existing classes.
2. Extensibility: Allows extending existing functionality in a structured way.
3. Maintainability: Simplifies updates by modifying parent class behavior.

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7. Best Practices #

1. Use Descriptive Class Names:
   • Make class names meaningful and self-explanatory.
2. Avoid Deep Inheritance Chains:
   • Simplify inheritance structures to reduce complexity.
3. Leverage super():
   • Use super() for extending functionality without hardcoding parent class names.
4. Document Relationships:
   • Clearly document the relationships between parent and child classes.

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Conclusion #

Inheritance is a powerful feature in Python that promotes code reusability and modularity. By understanding its types, features, and best practices, developers can build robust and maintainable object-oriented programs.