Django错误：获取关键字参数的多个值 [英] Django error: got multiple values for keyword argument

问题描述

  __ init __（）获得多个值，以获取以下错误：关键字参数'collection_type'
  

__ init __（）函数（如下所示）完全是这样写的，但是用我的逻辑代替＃code 。除此之外，我基本上覆盖了表单（它是一个ModelForm）构造函数。

  def __init __（self，collection_type，user =没有，parent = None，* args，** kwargs）
＃code 
 super（self .__ class__，self）.__ init __（* args，** kwargs）
  

此处显示了创建错误的调用：

 code> form = CreateCollectionForm（
 request.POST，
 collection_type = collection_type，
 parent = parent，
 user = request.user 
）
  

我看不到任何错误出现的原因。

编辑：这是构造函数的完整代码

  def __init __（self，collection_type，user = None，parent =没有，* args，** kwargs）：
 self.collection_type = collection_type 
 if self.collection_type =='library'：
 self.user = user 
 elif self.collection_type =='书架'或自我收藏_type =='series'：
 self.parent = parent 
 else：
 raise AssertionError，'collection_type必须是library，bookshelf或series'
 super （self .__ class__，self）.__ init __（* args，** kwargs）
  

编辑：Stacktrace

 环境：
 
请求方法：POST 
请求URL：http：// localhost： 8000 / forms / create_bookshelf / hello 
 Django版本：1.1.1 
 Python版本：2.6.1 
安装的应用程序：
 ['django.contrib.auth'，
'django.contrib.contenttypes'，
'django.contrib.sessions'，
'django.contrib.sites'，
'libraries'，
'users'，
'books'，
'django.contrib.admin'，
'googlehooks'，
'registration'] 
安装的中间件：
（'django。 middleware.common.CommonMiddleware'，
'django.contrib.sessions.middleware.SessionMiddleware'，
'django.contrib.auth.middleware.Authenticat ionMiddleware'）
 
 
追溯：
文件/Library/Python/2.6/site-packages/django/core/handlers/base.pyin get_response 
 92. response = callback（request，* callback_args，** callback_kwargs）
文件/Library/Python/2.6/site-packages/django/contrib/auth/decorators.py在__call__ 
 78。 return self.view_func（request，* args，** kwargs）
在create_collection中的文件/Users/marcus/Sites/marcuswhybrow.net/autolib/libraries/forms.py
 13. form = CreateCollectionForm （request.POST，collection_type = collection_type，user = request.user）
 
异常类型：type / at / forms / create_bookshelf / hello 
异常值：__init __（）获取了多个关键字参数值'collection_type'
  

解决方案

你正在传递 collection_type 参数作为一个关键字参数，因为你特别说 collection_type = collection_type 所以Python将它包含在 kwargs 字典中 - 但是因为你也已经将其声明为该函数定义中的位置参数，它会尝试将其传递两次，从而导致错误。 / p>



但是，你想做的事情永远都不会有效。在 * args 字典之前，您不能有 user = None，parent = None ，因为那些已经是kwargs，并且args必须始终在kwargs之前。修复它的方法是删除collection_type，user和parent的明确定义，并从函数中的kwargs中提取它们：

  collection_type = kwargs.pop（'collection_type'，None）
 user = kwargs.pop（'user'，None）
 parent = kwargs.pop（'parent'，None）
  




I get the following error when instantiating a Django form with a the constructor overriden:

__init__() got multiple values for keyword argument 'collection_type'

The __init__() function (shown below) is exactly as written this but with # code replaced with my logic. Asside from that I am essentially overriding the form's (which is a ModelForm) constructor.

def __init__(self, collection_type, user=None, parent=None, *args, **kwargs):
    # code
    super(self.__class__, self).__init__(*args, **kwargs)

The call that creates the error is shown here:

form = CreateCollectionForm(
    request.POST, 
    collection_type=collection_type, 
    parent=parent, 
    user=request.user
)

I cannot see any reason why the error is popping up.

EDIT: Here is the full code for the constructor

def __init__(self, collection_type, user=None, parent=None, *args, **kwargs):
    self.collection_type = collection_type
    if self.collection_type == 'library':
        self.user = user
    elif self.collection_type == 'bookshelf' or self.collection_type == 'series':
        self.parent = parent
    else:
        raise AssertionError, 'collection_type must be "library", "bookshelf" or "series"'
    super(self.__class__, self).__init__(*args, **kwargs)

EDIT: Stacktrace

Environment:

Request Method: POST
Request URL: http://localhost:8000/forms/create_bookshelf/hello
Django Version: 1.1.1
Python Version: 2.6.1
Installed Applications:
['django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.sites',
 'libraries',
 'users',
 'books',
 'django.contrib.admin',
 'googlehooks',
 'registration']
Installed Middleware:
('django.middleware.common.CommonMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware')


Traceback:
File "/Library/Python/2.6/site-packages/django/core/handlers/base.py" in get_response
  92.                 response = callback(request, *callback_args, **callback_kwargs)
File "/Library/Python/2.6/site-packages/django/contrib/auth/decorators.py" in __call__
  78.             return self.view_func(request, *args, **kwargs)
File "/Users/marcus/Sites/marcuswhybrow.net/autolib/libraries/forms.py" in     create_collection
  13.           form = CreateCollectionForm(request.POST,     collection_type=collection_type, user=request.user)

Exception Type: TypeError at /forms/create_bookshelf/hello
Exception Value: __init__() got multiple values for keyword argument 'collection_type'

解决方案

You're passing the collection_type argument in as a keyword argument, because you specifically say collection_type=collection_type in your call to the form constructor. So Python includes it within the kwargs dictionary - but because you have also declared it as a positional argument in that function's definition, it attempts to pass it twice, hence the error.

However, what you're trying to do will never work. You can't have user=None, parent=None before the *args dictionary, as those are already kwargs, and args must always come before kwargs. The way to fix it is to drop the explicit definition of collection_type, user and parent, and extract them from kwargs within the function:

def __init__(self, *args, **kwargs):
    collection_type = kwargs.pop('collection_type', None)
    user = kwargs.pop('user', None)
    parent = kwargs.pop('parent', None)

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