類繼承的遞歸錯誤

我有一個包含我想用來存儲API端點的類的文件。我想使用類的原因是，我可以通過輸入api.level2.resources來訪問端點。類繼承的遞歸錯誤

下面是該文件的樣子，與API作爲主類和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，當我嘗試使用這樣的：

from src import API 

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

我收到以下錯誤：

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

我很確定解決方案很簡單，我只是不確定如何構建類能夠像我想要的那樣使用它。

來源

2017-07-18 rhillhouse

那麼，你期望什麼？每當你實例化你的API對象時，它的'__init __（）'方法被調用，然後實例化一個調用__init __（）方法的'SubEntries'對象，該方法調用其父'__init __（）'方法來實例化另一個'SubEntries'實例等，等等...... – zwer

[如何調用超級構造函數？]的可能重複（https://stackoverflow.com/questions/2399307/how-to-invoke-the-super-構造函數） –

@zwer我意識到這一點，但我不知道如何以任何其他方式訪問子類的值。我只想初始化父級，但仍然將子類及其值加載到level2中。 – rhillhouse

正如我在我的評論中所說的，你在這裏非常明確地創建了一個循環引用，所以它在某一點上達到了Python的遞歸極限。有很多方法可以避免類似對象的遞歸。最簡單的是有一個共同的父母，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'

您還可以覆蓋在你的BaseAPI類__getattr__()/__setattr__()/__delattr__()方法，然後讓每個屬性訪問動態評估。您還可以傳遞一個「端點」 dict您BaseAPI類，並把它從一個傳遞dict更新其self.__dict__獲得端點...

你的問題缺乏特異性表明這將是最好的辦法。

來源

2017-07-18 15:46:50 zwer

類繼承的遞歸錯誤

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