Python中Set集合操作中的实现相减操作的demo

demo_set_hash_magic.py

#-*- coding:utf-8 -*-

class Address(object):
    def __init__(self, name):
        self.name = name

    def __eq__(self, other):
        return self.name == other.name

    def __ne__(self, other):
        return not self.__eq__(other)

    def __hash__(self):
        return hash(self.name)


class Person(object):
    def __init__(self, no, name, sex, addrs):
        self.no = no
        self.name = name
        self.sex = sex
        self.addrs = addrs

    def __repr__(self):
        return self.no

    def __eq__(self, other):
        print("call __eq__")
        if self.name == other.name and self.sex == other.sex:
            if self.addrs is None and other.addrs is None:
                return True
            if not ( self.addrs and other.addrs):
                return False
            saddrs = sorted(self.addrs, key=lambda addr: addr.name)
            oaddrs = sorted(other.addrs, key=lambda addr: addr.name)
            eq = saddrs == oaddrs
            return eq
        return False

    def __ne__(self, other):
        return not self.__eq__(other)

    def __hash__(self):
          return hash((self.name,self.sex))


if __name__ == '__main__':
    addrs = [Address("a"), Address("b"), Address("c")]
    addrs2 = [Address("a"), Address("c"), Address("b")]

    p1 = Person("p1", "p", 2, addrs)
    p2 = Person("p2", "p", 2, addrs2)
    p3 = Person("p3", "p", 1, addrs)
    p4 = Person("p4", "p", 2, addrs2)
    p5 = Person("p5", "p", 2, addrs)

    set_one = {p1, p3, p4}
    set_two = {p2, p3, p5}

    new_set = set_two - set_one ## 期待得到空的集合

    print("element in new_set")
    for each in new_set:
        print str(each)
    else:
        print("iter finish")