Python多态案例如何实现多态特性

wen python案例 2026-06-30 218

Python多态特性实现案例

多态是面向对象编程的重要特性，允许不同类的对象对同一方法做出不同响应,以下是几个典型的多态实现案例：

Python多态案例如何实现多态特性

基本的多态实现（通过继承）

class Animal:
    def speak(self):
        raise NotImplementedError("子类必须实现这个方法")
class Dog(Animal):
    def speak(self):
        return "汪汪汪"
class Cat(Animal):
    def speak(self):
        return "喵喵喵"
class Duck(Animal):
    def speak(self):
        return "嘎嘎嘎"
# 多态的使用
def animal_sound(animal):
    """传入不同的动物对象，调用相同的speak方法"""
    return animal.speak()
# 测试多态
animals = [Dog(), Cat(), Duck()]
for animal in animals:
    print(f"{animal.__class__.__name__}: {animal_sound(animal)}")

鸭子类型（Duck Typing）实现多态

class Bird:
    def fly(self):
        return "鸟儿在飞"
class Airplane:
    def fly(self):
        return "飞机在飞"
class Superman:
    def fly(self):
        return "超人在飞"
# 多态函数 - 不关心对象类型，只关心是否有fly方法
def make_it_fly(flying_object):
    return flying_object.fly()
# 测试鸭子类型多态
objects = [Bird(), Airplane(), Superman()]
for obj in objects:
    print(f"{obj.__class__.__name__}: {make_it_fly(obj)}")

使用抽象基类（ABC）实现多态

from abc import ABC, abstractmethod
class Shape(ABC):
    @abstractmethod
    def area(self):
        pass
    @abstractmethod
    def perimeter(self):
        pass
class Circle(Shape):
    def __init__(self, radius):
        self.radius = radius
    def area(self):
        return 3.14 * self.radius ** 2
    def perimeter(self):
        return 2 * 3.14 * self.radius
class Rectangle(Shape):
    def __init__(self, width, height):
        self.width = width
        self.height = height
    def area(self):
        return self.width * self.height
    def perimeter(self):
        return 2 * (self.width + self.height)
# 多态计算
def calculate_shape_info(shape):
    return f"面积: {shape.area()}, 周长: {shape.perimeter()}"
# 测试
shapes = [Circle(5), Rectangle(4, 6)]
for shape in shapes:
    print(f"{shape.__class__.__name__}: {calculate_shape_info(shape)}")

运算符重载实现多态

class Vector:
    def __init__(self, x, y):
        self.x = x
        self.y = y
    def __add__(self, other):
        """重载+运算符，实现向量加法"""
        if isinstance(other, Vector):
            return Vector(self.x + other.x, self.y + other.y)
        elif isinstance(other, (int, float)):
            return Vector(self.x + other, self.y + other)
        else:
            raise TypeError("不支持的类型")
    def __str__(self):
        return f"Vector({self.x}, {self.y})"
# 测试运算符多态
v1 = Vector(1, 2)
v2 = Vector(3, 4)
# 向量加向量
result1 = v1 + v2
print(f"向量相加: {result1}")
# 向量加数字
result2 = v1 + 10
print(f"向量加数字: {result2}")

实际应用案例 - 支付系统

class PaymentSystem:
    def pay(self, amount):
        raise NotImplementedError
class Alipay(PaymentSystem):
    def pay(self, amount):
        return f"使用支付宝支付 {amount} 元"
class WeChatPay(PaymentSystem):
    def pay(self, amount):
        return f"使用微信支付 {amount} 元"
class BankCard(PaymentSystem):
    def pay(self, amount):
        return f"使用银行卡支付 {amount} 元"
# 多态处理支付
def process_payment(payment_method, amount):
    """
    统一的支付处理函数
    任何实现了pay方法的对象都可以传入
    """
    result = payment_method.pay(amount)
    return f"【支付成功】{result}"
# 测试
payments = [Alipay(), WeChatPay(), BankCard()]
for payment in payments:
    print(process_payment(payment, 100))

使用函数参数多态

def calculate_area(shape, *args):
    """
    根据传入的不同形状计算面积
    这是函数级别的多态
    """
    if shape == "circle":
        radius = args[0]
        return 3.14 * radius ** 2
    elif shape == "rectangle":
        width, height = args
        return width * height
    elif shape == "triangle":
        base, height = args
        return 0.5 * base * height
    else:
        return None
# 测试
print(f"圆面积: {calculate_area('circle', 5)}")
print(f"矩形面积: {calculate_area('rectangle', 4, 6)}")
print(f"三角形面积: {calculate_area('triangle', 3, 8)}")

Python实现多态的几种方式：