类继承的递归错误

我有一个包含我想用来存储API端点的类的文件。我想使用类的原因是，我可以通过输入api.level2.resources来访问端点。类继承的递归错误

下面是该文件的样子，与API作为主类和SubEntries的“孩子”：

class API(object): 
    """ 
    A class for logging to stdout and/or a file. Supports color output for different log kinds. 
    """ 

    def __init__(self): 
     """ 
     :param log_to_file: Bool - Whether to log to a file or only to stdout (False) 
     :param s: String - Log file name without extension for success logs 
     :param e: String - Log file name without extension for error logs 
     :param prefix: Bool - Whether to show the prefix or not 
     :param timestamp: Bool - Whether to show the timestamp or not 
     :param debug: Bool - Whether to show debug messages or not 
     """ 
     self.login = '/login' 
     self.logout = '/logout' 
     self.sysRequest = '/sysReq' 
     self.level2 = SubEntries() 


class SubEntries(API): 

    def __init__(self): 
     super().__init__() 
     self.host_info = '/info' 
     self.resources = '/resources'

但是，当我尝试使用这样的：

from src import API 

api = API() 
print(api.level2.resources)

我收到以下错误：

Traceback (most recent call last): 
    File "D:/_projects/pynap/new.py", line 4, in <module> 
    api = API() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    ... 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
    File "D:\_projects\pynap\src\QAPI.py", line 24, in __init__ 
    super().__init__() 
    File "D:\_projects\pynap\src\QAPI.py", line 18, in __init__ 
    self.level2 = SubEntries() 
RecursionError: maximum recursion depth exceeded while calling a Python object

我很确定解决方案很简单，我只是不确定如何构建类能够像我想要的那样使用它。

来源

2017-07-18 rhillhouse

那么，你期望什么？每当你实例化你的API对象时，它的'__init __（）'方法被调用，然后实例化一个调用__init __（）方法的'SubEntries'对象，该方法调用其父'__init __（）'方法来实例化另一个'SubEntries'实例等，等等...... – zwer

[如何调用超级构造函数？]的可能重复（https://stackoverflow.com/questions/2399307/how-to-invoke-the-super-构造函数） –

@zwer我意识到这一点，但我不知道如何以任何其他方式访问子类的值。我只想初始化父级，但仍然将子类及其值加载到level2中。 – rhillhouse

正如我在我的评论中所说的，你在这里非常明确地创建了一个循环引用，所以它在某一点上达到了Python的递归极限。有很多方法可以避免类似对象的递归。最简单的是有一个共同的父母，例如：

class BaseAPI(object): 
    # place here whatever you want common for all API/SubEntry objects 
    pass 

class API(BaseAPI): 

    def __init__(self): 
     self.login = '/login' 
     self.logout = '/logout' 
     self.sysRequest = '/sysReq' 
     self.level2 = SubEntries() 

class SubEntries(BaseAPI): 

    def __init__(self): 
     super(BaseAPI, self).__init__() 
     self.host_info = '/info' 
     self.resources = '/resources'

您还可以覆盖在你的BaseAPI类__getattr__()/__setattr__()/__delattr__()方法，然后让每个属性访问动态评估。您还可以传递一个“端点” dict您BaseAPI类，并把它从一个传递dict更新其self.__dict__获得端点...

你的问题缺乏特异性表明这将是最好的办法。

来源

2017-07-18 15:46:50 zwer

类继承的递归错误

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