python中类方法重写_Python中的方法重写

python中类方法重写

Python中的方法重写 (Method Overriding in Python)

Method overriding is a concept of object oriented programming that allows us to change the implementation of a function in the child class that is defined in the parent class. It is the ability of a child class to change the implementation of any method which is already provided by one of its parent class(ancestors).

方法重写是面向对象编程的概念，它允许我们更改父类中定义的子类中函数的实现。 子类具有更改其父类（祖先）之一已提供的任何方法的实现的能力。

Following conditions must be met for overriding a function:

覆盖功能必须满足以下条件：

1. Inheritance should be there. Function overriding cannot be done within a class. We need to derive a child class from a parent class.继承应该在那里。 函数重写不能在类内完成。 我们需要从父类派生子类。
2. number of parameters.参数数量相同。

As we have already learned about the concept of Inheritance, we know that when a child class inherits a parent class it also get access to it public and protected(access modifiers in python) variables and methods, for example,

正如我们已经了解了继承的概念一样 ，我们知道，当子类继承父类时，它也可以访问它的public和protected变量和方法（例如python中的访问修饰符 ），

# parent class
class Parent:
    # some random function
    def anything(self):
        print('Function defined in parent class!')
        
# child class
class Child(Parent):
    # empty class definition
    pass


obj2 = Child()
obj2.anything()

Function defined in parent class!

在父类中定义的功能！

While the child class can access the parent class methods, it can also provide a new implementation to the parent class methods, which is called method overriding.

虽然子类可以访问父类的方法，但是它也可以为父类的方法提供一个新的实现，称为方法重写 。

Python方法重载示例 (Python Method Overriding Example)

Let's take a very cool example which we also had in the inheritance tutorial. There is a parent class named Animal:

让我们举一个非常酷的示例，该示例在继承教程中也有。 有一个名为Animal的父类：

class Animal:
    # properties
	multicellular = True
	# Eukaryotic means Cells with Nucleus
	eukaryotic = True
	
	# function breathe
	def breathe(self):
	    print("I breathe oxygen.")
    
    # function feed
	def feed(self):
	    print("I eat food.")

Let's create a child class Herbivorous which will extend the class Animal:

让我们创建一个子类Herbivorous ，它将扩展Animal类：

class Herbivorous(Animal):
    
    # function feed
	def feed(self):
	    print("I eat only plants. I am vegetarian.")

In the child class Herbivorous we have overridden the method feed().

在子类Herbivorous我们重写了feed()方法。

So now when we create an object of the class Herbivorous and call the method feed() the overridden version will be executed.

因此，现在当我们创建类Herbivorous的对象并调用feed()方法时，将执行覆盖的版本。

herbi = Herbivorous()
herbi.feed()
# calling some other function
herbi.breathe()

I eat only plants. I am vegetarian. I breathe oxygen.

我只吃植物。 我是素食主义者。 我呼吸氧气。

Click on Run to see the code in action and feel free to make changesto it and run again.

单击“ 运行”以查看运行中的代码，并随时对其进行更改并再次运行。

翻译自: https://www.studytonight.com/python/method-overriding-in-python

python中类方法重写