实现类的比较操作

from abc import abstractmethod
from functools import total_ordering
from math import pi

@total_ordering
class Shape(object):

    @abstractmethod
    def area(self): #抽象方法
        pass

    def __lt__(self, other):
        print ‘in__lt__‘
        if not isinstance(other, Shape):
            raise TypeError(‘other is not Shape‘)
        return self.area() < other.area()

    def __eq__(self, other):
        print ‘in__eq__‘
        if not isinstance(other, Shape):
            raise TypeError(‘other is not Shape‘)
        return self.area() == other.area()
    
‘‘‘矩形面积‘‘‘
class Rectangle(Shape):
    def __init__(self, w, h):
        self.w = w
        self.h = h

    def area(self):
        return self.w * self.h

‘‘‘圆形面积‘‘‘
class Cirle(Shape):

    def __init__(self, r):
        self.r = r

    def area(self):
        return self.r ** 2 * pi

r = Rectangle(4, 5)
c = Cirle(2)

‘‘‘对矩形面积与圆形面积的比较‘‘‘
print r < c
print ‘-‘*20
print r <= c
print ‘-‘*20
print r == c
print ‘-‘*20
print r >= c
print ‘-‘*20
print r > c