Python __str__函数

class Cat:
        def __init__(self,_name):
                self.name = _name
        def __str__(self):
                return "i am %s"%self.name
        def show(self):
                print("name is %s"%self.name)


tom = Cat("tom")

tom.show()

print(tom)


print("------------");

lanmao = Cat("lanpang")

lanmao.show()

print(lanmao)

__str__函数要求有返回值，必须有return,
__str__函数功能是将对象字符串化

 python类中所有的属性和方法默认都是Public，可以在函数外访问

class Cat:
        def __init__(self,_name):
                self.name = _name
                self.fish = []
        def __str__(self):
                #__str必须返回一个字符串，不能是其他任何值
                #注意列表的字符串化
                return "i am %s and i eat %s ."%(self.name,str(self.fish))
        def eat(self,_fish):
                self.fish.append(_fish.name)

class Fish:
        def __init__(self,_name):
                self.name = _name



tom = Cat("tom")

fish = Fish("鲫鱼")

tom.eat(fish)

print(tom)