問題描述

class Programer(object):

hobby=’play computer’def __init__(self,name,age,weight): self.name=name self._age=age self.__weight=weightdef self_intro(self): print ’my name is %s nI am %s years oldn’ % (self.name, self._age)

class BackendProgramer(Programer):

def __init__(self,name,age,weight,language): super(BackendProgramer,self).__init__(name,age,weight) self.language = languagedef self_intro(self): print ’my name is %s nmy favourite language is %sn’ % (self.name, self.language)

def intro(f):

if isinstance(f,Programer): print f.self_intro

if __name__==’__main__’:

prog = Programer(’Albert’,25,’80’)back_prog = BackendProgramer(’Alex’,23,’80’,’Ruby’)intro(prog)intro(back_prog)

運行結果是：<bound method Programer.self_intro of <__main__.Programer object at 0x02505330>><bound method BackendProgramer.self_intro of <__main__.BackendProgramer object at 0x02505370>>

請問為什么運行結果不是my name is ...

問題解答

因為你忘記調用了

def intro(f): if isinstance(f,Programer):print f.self_intro() # 沒有()只是函數對象而已, 加了()才是調用