Inheritance is an important mechanism in Python to implement code reuse and structure optimization. It allows subclasses to obtain the properties and methods of the parent class, thereby reducing redundant code, improving maintainability, and being closer to realistic modeling. When defining inheritance, just specify the parent class name in brackets after the subclass name, such as class Dog(Animal). If the subclass overrides the __init__ method, super().__init__() needs to be explicitly called to complete the initialization of the parent class. Method override can be used to modify or extend parent class behavior, and super() can preserve parent class logic. Python supports multiple inheritance, but complex conflicts should be avoided, and the MRO order and single responsibilities should be paid attention to. For example, Dog and Cat classes inherit Animal base class, share name attributes, and override the spoke method to return different calls. Rational use of inheritance can improve the clarity of the program structure, but abuse may lead to confusion, especially in multiple inheritance scenarios, which should be handled with caution.

Inheritance is a very practical feature in object-oriented programming in Python, which can help us reuse code and reduce duplicate logic. If you already understand the basic concepts of classes and objects, you can build clearer and better-structured programs through inheritance.

What is inheritance?

Simply put, inheritance is to let one class (subclass) obtain the properties and methods of another class (parent class). The benefits of doing this are:

• Reduce code redundancy
• Improve maintainability
• Modeling closer to the real world

For example, if you have multiple animal classes (dogs, cats), they all have "names" and "cry", then you can define an Animal parent class and let Dog and Cat inherit it.

 class Animal:
    def __init__(self, name):
        self.name = name

    def speak(self):
        pass

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

class Cat(Animal):
    def speak(self):
        return "Meow!"

How to define an inheritance relationship?

In Python, defining inheritance is very intuitive. Just write the parent class name in parentheses when defining the class:

 class subclass name (parent class name):
    ...

If there are multiple parent classes, it can also be written as:

 class subclass name (parent class 1, parent class 2, ...):
    ...

What should be noted is:

• Subclasses will have all public properties and methods of the parent class
• If the subclass has its own __init__ method, it is usually necessary to manually call the constructor of the parent class, otherwise the parent class initialization logic will not be automatically executed

For example:

 class Parent:
    def __init__(self, name):
        self.name = name

class Child(Parent):
    def __init__(self, name, age):
        super().__init__(name) # The parent class must be called explicitly to initialize self.age = age

Method rewriting and super()

Sometimes we want the subclass to modify the parent class's methods, and then we need to override the method .
For example, in the above example, speak() is a rewritten method.

If you just want to extend the parent class method instead of completely replacing it, you can use super() to call the parent class method:

 class Animal:
    def speak(self):
        print("Animal speaks")

class Dog(Animal):
    def speak(self):
        super().speak() # Execute the parent class method print("Dog barks")

Running Dog().speak() will first output "Animal speaks" and then output "Dog barks" .

Multiple inheritance skills

Python supports multiple inheritance, but be careful when using it. There may be naming conflicts or call order issues between multiple parent classes.

Python uses MRO (Method Resolution Order) to decide which parent class method to call. You can use ClassName.mro() to view the search order.

suggestion:

• Don't overuse multiple inheritance
• If necessary, try to keep each parent class single responsibilities as much as possible
• Be careful to avoid the chaos caused by "diamond inheritance"

Example:

 class A:
    def do(self):
        print("A")

class B(A):
    def do(self):
        print("B")

class C(A):
    def do(self):
        print("C")

class D(B, C):
    pass

d = D()
d.do() # Output B, because B is in the inheritance list

Basically that's it. Inheritance itself is not complicated, but only by using it rationally in actual projects can it truly bring out its value.

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