实例对象的切片操作和索引重写的方法一样的

class Person(object):
    def __init__(self):
        self.cache =[]
        pass
    def __setitem__(self, key, value):
        print(key.start)
        print(key.stop)
        print(key.step)
        print(value)
        self.cache[key]=value
        self.age = 10
    def __getitem__(self, item):
        return self.cache[item]
    def __delitem__(self, key):
        print(key)
        del self.cache[key]
if __name__ == '__main__':
    p = Person()
    p[0:4:1] =[1,2,3,4]
    # a = (1,2)
    # print(type(a))
    # b=[1,2]
    # print(type(b))
    # c={1,23}
    # print(type(c))
    print(p.__dict__)
    print(p[2:-1])
    del p[1:3]
    print(p.__dict__)