“超级”对象的描述符“__init__”需要参数

Posted 2023-02-23

【中文标题】“超级”对象的描述符“__init__”需要参数

【英文标题】：descriptor '__init__' of 'super' object needs argument

【发布时间】：2014-07-15 19:22:38

【问题描述】：

我正在尝试用 Python 制作一个面向对象的基于文本的游戏，并尝试实现我的第一个属性和装饰器。使用'Python 3 Object Oriented Programming' 中的第 5 章，我尝试使用讨论的示例和概念来获取以下代码，以便在实例化时设置游戏对象的 'current_room' 属性：

class Room(object):
    ''' An area of the game's map.'''
    def __init__(self):
        print("Accessing the Room __init__ method.")


class FirstRoom(Room):
    ''' Just some room.'''
    def __init__(self):
        print("Accessing the FirstRoom __init__ method.")
        super.__init__()


class SecondRoom(Room):
    ''' Just some other room.'''
    def __init__(self):
        print("Accessing the SecondRoom __init__ method.")
        super.__init__()


class Game(object):
    ''' Creates a new game.'''
    current_room = None # Class-level definition of this property.

    def __init__(self):
        print("Created a new Game object.")
        self.current_room = FirstRoom()

    @property
    def current_room(self):
        ''' Returns the current position of the actor.'''
        print("Getting the _current_room attribute for the Game object.")
        return self._current_room

    @current_room.setter   
    def set_room(self, new_room):
        ''' Sets the current_room property of the Game object.'''
        print("Setting the _current_room attribute for the Game object.")
        self._current_room = new_room

但是，当我运行此代码时，我得到以下输出：

>>> g = Game()
Created a new Game object.
Accessing the FirstRoom __init__ method.
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/drew/Desktop/test.py", line 27, in __init__
    self.current_room = FirstRoom()
  File "/home/drew/Desktop/test.py", line 11, in __init__
    super.__init__()
TypeError: descriptor '__init__' of 'super' object needs an argument

我的代码中缺少什么以使此语法正常工作？我需要为我的“current_room”属性显式定义一个描述符吗？ [这本书没有提到任何关于描述符的内容，至少不像你在这里看到的那样：Python Descriptors Demystified。]

【问题讨论】：

您实际上需要致电 super。

How to call Base Class's __init__ method from the child class?的可能重复

看起来像语法 super().__init__() 并将 self.current_room = FirstRoom() 更改为 self._current_room = FirstRoom() 修复了下一个错误。谢谢！

@RSahu 我不认为这个问题是重复的（至少是那个问题）。事实上，OP 的问题不是调用super 而您链接的问题确实 调用super 并且产生的错误完全不同。

【参考方案1】：

super 错误实际上是在您调用 super 之前将 print 打印出来，以下代码可以正常工作：

class Room(object):
    ''' An area of the game's map.'''
    def __init__(self):
        print("Accessing the Room __init__ method.")


class FirstRoom(Room):
    ''' Just some room.'''

    def __init__(self):
        super().__init__()
        print("Accessing the FirstRoom __init__ method.")



class SecondRoom(Room):
    ''' Just some other room.'''

    def __init__(self):
        super().__init__()
        print("Accessing the SecondRoom __init__ method.")

您需要了解@property 等的工作原理。

Property python docs

从文档中，确保为附加函数提供与原始属性相同的名称

class Game(object):
    ''' Creates a new game.'''
    current_room = None  # Class-level definition of this property.

def __init__(self):
    print("Created a new Game object.")
    self._current_room = FirstRoom()

@property
def current_room(self, room): 
    ''' Returns the current position of the actor.'''
    print("Getting the _current_room attribute for the Game object.")
    return self._current_room


@current_room.setter # same function name as the property.
def current_room(self, new_room):# same name  as the property
    ''' Sets the current_room property of the Game object.'''
    print("Setting the _current_room attribute for the Game object.")
    self._current_room=new_room  

【讨论】：

是的，使用 Python 3.4.0。

不用担心。看看文档，有几个很好的例子来说明 @property 等是如何工作的。

【参考方案2】：

这里是工作代码：

class Room(object):
    ''' An area of the game's map.'''
    def __init__(self):
        print("Accessing the Room __init__ method.")


class FirstRoom(Room):
    ''' Just some room.'''
    def __init__(self):
        print("Accessing the FirstRoom __init__ method.")
        #super.__init__()
        super(FirstRoom, self).__init__()


class SecondRoom(Room):
    ''' Just some other room.'''
    def __init__(self):
        print("Accessing the SecondRoom __init__ method.")
        super(SecondRoom, self).__init__()
        #super.__init__()


class Game(object):
    ''' Creates a new game.'''
    _current_room = None # Class-level definition of this property.

    def __init__(self):
        print("Created a new Game object.")
        self._current_room = FirstRoom()

    @property
    def current_room(self):
        ''' Returns the current position of the actor.'''
        print("Getting the _current_room attribute for the Game object.")
        return self._current_room

    @current_room.setter   
    def set_room(self, new_room):
        ''' Sets the current_room property of the Game object.'''
        print("Setting the _current_room attribute for the Game object.")
        self._current_room = new_room

当运行时：

>>> g = Game()
Created a new Game object.
Accessing the FirstRoom __init__ method.
Accessing the Room __init__ method.
>>> 

希望对您有所帮助。

【参考方案3】：

使用super().__init__() 代替super.__init__()

【讨论】：

谢谢你，亲爱的