Python 3 面向对象基础教程

欢迎来到本站学习 Python 3 面向对象编程基础。以下是一些基础概念和示例，帮助你更好地理解面向对象编程。

类和对象

在 Python 中，类是创建对象的蓝图。对象是类的实例。

class Dog:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def bark(self):
        return f"{self.name} says: Woof!"

# 创建对象
my_dog = Dog("Buddy", 5)
print(my_dog.bark())  # 输出: Buddy says: Woof!

继承

继承是面向对象编程中的一个重要概念。它允许一个类继承另一个类的属性和方法。

class Puppy(Dog):
    def __init__(self, name, age, color):
        super().__init__(name, age)
        self.color = color

    def play(self):
        return f"{self.name} is playing with a ball."

# 创建对象
puppy = Puppy("Max", 2, "brown")
print(puppy.bark())  # 输出: Max says: Woof!
print(puppy.play())  # 输出: Max is playing with a ball.

多态

多态是指同一个方法在不同的对象上有不同的行为。

class Animal:
    def speak(self):
        return "Some sound"

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

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

# 创建对象
dog = Dog()
cat = Cat()

print(dog.speak())  # 输出: Woof!
print(cat.speak())  # 输出: Meow!

实例方法与类方法

实例方法是绑定到对象的，而类方法是绑定到类的。

class MyClass:
    def __init__(self, value):
        self.value = value

    def instance_method(self):
        return f"Instance method, value: {self.value}"

    @classmethod
    def class_method(cls):
        return "Class method"

# 创建对象
obj = MyClass(10)
print(obj.instance_method())  # 输出: Instance method, value: 10
print(MyClass.class_method())  # 输出: Class method

装饰器

装饰器是用于修改函数或方法行为的函数。

def my_decorator(func):
    def wrapper():
        print("Something is happening before the function is called.")
        func()
        print("Something is happening after the function is called.")
    return wrapper

@my_decorator
def say_hello():
    print("Hello!")

say_hello()  # 输出: Something is happening before the function is called. Hello! Something is happening after the function is called.

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