Python 中的 abc 模块之抽象类与接口

from abc import ABC, abstractmethod
class Shape(ABC):
    """形状的抽象基类"""
    @property
    @abstractmethod
    def area(self):
        """返回形状的面积"""
        pass
    @abstractmethod
    def draw(self):
        """绘制形状"""
        pass
class Circle(Shape):
    """圆形类"""
    def __init__(self, radius):
        self.radius = radius
    @property
    def area(self):
        return 3.14 * (self.radius ** 2)
    def draw(self):
        print(f'Drawing a circle with radius {self.radius}')
class Rectangle(Shape):
    """矩形类"""
    def __init__(self, width, height):
        self.width = width
        self.height = height
    @property
    def area(self):
        return self.width * self.height
    def draw(self):
        print(f'Drawing a rectangle with width {self.width} and height {self.height}')

class Triangle:
    """三角形类"""
    def __init__(self, base, height):
        self.base = base
        self.height = height
    @property
    def area(self):
        return 0.5 * self.base * self.height
    def draw(self):
        print(f'Drawing a triangle with base {self.base} and height {self.height}')
# 注册 Triangle 为 Shape 的成员
Shape.register(Triangle)
t = Triangle(5, 10)
print(f'Triangle area: {t.area}')  # 输出: Triangle area: 25.0
print(isinstance(t, Shape))  # 输出: True