python中的类继承

Question

我正在解决这个问题：

考虑以下类的层次结构：

class Person(object):     
    def __init__(self, name):         
        self.name = name     
    def say(self, stuff):         
        return self.name + ' says: ' + stuff     
    def __str__(self):         
        return self.name  

class Lecturer(Person):     
    def lecture(self, stuff):         
        return 'I believe that ' + Person.say(self, stuff)  

class Professor(Lecturer): 
    def say(self, stuff): 
        return self.name + ' says: ' + self.lecture(stuff)

class ArrogantProfessor(Professor): 
    def say(self, stuff): 
        return 'It is obvious that ' + self.say(stuff)

正如所写，这段代码在使用 嚣张教授班。

更改 ArrogantProfessor 的定义，使以下 行为达成：

e = Person('eric') 
le = Lecturer('eric') 
pe = Professor('eric') 
ae = ArrogantProfessor('eric')

e.say('the sky is blue')              #returns   eric says: the sky is blue

le.say('the sky is blue')             #returns   eric says: the sky is blue

le.lecture('the sky is blue')         #returns   believe that eric says: the sky is blue

pe.say('the sky is blue')             #returns   eric says: I believe that eric says: the sky is blue

pe.lecture('the sky is blue')     #returns   believe that eric says: the sky is blue

ae.say('the sky is blue')         #returns   eric says: It is obvious that eric says: the sky is blue

ae.lecture('the sky is blue')     #returns   It is obvious that eric says: the sky is blue

我的解决办法是：

class ArrogantProfessor(Person):
    def say(self, stuff):
        return Person.say(self, ' It is obvious that ') +  Person.say(self,stuff)
    def lecture(self, stuff):
        return 'It is obvious that  ' + Person.say(self, stuff)

但检查员只给这个解决方案一半的分数。我犯了什么错误，该代码失败的测试用例是什么？ （我是 python 新手，前段时间学习了类。）

Answer 1

您可能应该使用 super() 而不是硬连接类 Person：

class ArrogantProfessor(Person):
    def say(self, stuff):
        return super(ArrogantProfessor, self).say(self.lecture(stuff))
    def lecture(self, stuff):
        return 'It is obvious that ' + super(ArrogantProfessor, self).say(stuff)

Answer 2

它被赋予：

class ArrogantProfessor(Professor): 

但你这样做了：

class ArrogantProfessor(Person): 

这导致成绩减半。

Answer 3

我认为，作为以前的编码硬件分级员，您应该已经产生了所需的输出，而无需将ArrogantProfessor 变成仅仅是Person。毕竟，类名表明它仍然应该是Professor的子类。

Answer 4

他可能希望你真正获得父类。方法很简单。

Python2/3：

class ArrogantProfessor(Professor):
    def say(self, stuff):
        return 'It is obvious that ' + super(ArrogantProfessor, self).say(stuff)

仅限 Python 3：

class ArrogantProfessor(Professor):
    def say(self, stuff):
        return 'It is obvious that ' + super().say(stuff)

在任何一种情况下，ae.say("something") 都应该返回：

"It is obvious that eric says: I believe that eric says: something"

这是因为父类是Professor，而不是Person。

同样，在你的课堂上，你应该这样做：

def lecture(self, stuff):
    return 'I believe that ' + super(Lecturer, self).say(self, stuff) # or the Python3 version if you're using that

不过，还不清楚你想要什么。

Answer 5

在不知道他们想教你什么的情况下很难说。一个可能的猜测是你被教导继承，如果他们已经超过super，他们很可能希望你利用它来让 ArrogantProfessor 的输出看起来像：

eric says: It is obvious that STUFF

其中 STUFF 是您传入的字符串。

Answer 6

这应该是：

class ArrogantProfessor( Professor ):
    def lecture(self, stuff):
        return 'It is obvious that ' +  Person.say(self,stuff)

您不必在ArrogantProfessor 中定义say()，因为它已经在Professor 中定义，它将使用子类中定义的lecture() 方法。

Answer 7

     class Professor(Lecturer): 
        def say(self, stuff): 
            return "Prof. " + self.name + ' says: ' + self.lecture(stuff)

     class ArrogantProfessor( Professor ):
        def lecture(self, stuff):         
            return 'It is obvious that I believe that ' + Person.say(self, stuff)

Answer 8

对于第二部分，正确答案是：

class ArrogantProfessor(Professor):
    def lecture(self, stuff):
        return 'It is obvious that ' +  Lecturer.lecture(self,stuff)

Answer 9

第一部分的代码是：

class ArrogantProfessor( Professor ):
def lecture(self, stuff):
    return 'It is obvious that ' +  Person.say(self,stuff)

第二部分的代码是：

class ArrogantProfessor(Professor):
def lecture(self, stuff):
    return 'It is obvious that I believe that ' +  Person.say(self,stuff)

第三部分的代码是：

class Professor(Lecturer):
 def say(self, stuff): 
     return 'Prof. ' + self.name + ' says: ' + self.lecture(stuff)

希望有用