• __repr__ 对应repr(object)这个函数，返回一个可以用来表示对象的可打印字符串
• __str__ 对应str(object)这个函数，返回一个字符串对象，适合用于print输出
• __bytes__ 对应bytes(object)这个函数，返回bytes对象

class B:    def __init__(self,name):        self.name = name            def __repr__(self):        return 'call __repr__ name is {0}'.format(self.name)        def __str__(self):        return 'call __str__ name is {0}'.format(self.name)        def __bytes__(self):        return 'call __bytes__ name is {0}'.format(self.name).encode('utf-8')

b = B('zhaochj')

1 b 2 call __repr__ name is zhaochj

1 print(b)2 call __str__ name is zhaochj

1 str(b)2 'call __str__ name is zhaochj'

1 bytes(b)2 b'call __bytes__ name is zhaochj'