如何在django中序列化dataframe？在django中有返回dataframe和queryset的方法吗？

Question

我在这里试图做的是根据用户的选择(如日期、组和符号)获得一个查询。

我想使用django_pandas将这个查询集转换成一个数据帧。

我试图将生成的数据帧转换为JSON对象，但它提供了一些错误，如：

TypeError:类型为“DataFrame”的对象不能被JSON序列化

我的视图看起来如下：

class StockPriceDataViewSet(mixins.ListModelMixin,
                     viewsets.GenericViewSet):
    queryset = StockPriceData.objects.all()
    serializer_class = StockPriceDataSerializer
    filter_backends = [DjangoFilterBackend, SearchFilter]
    filterset_fields = {
        'date':['gte','lte'],
        'org__symbol':['exact'],
        'org__group':['exact'],
    }
    permission_classes = (AllowAny,)
    
    @action(methods=['GET'], detail=False, url_path='stock')
    def get_df(self, request):
        queryset = self.queryset
        result = generate_df(queryset=queryset)
        return Response(result, status=status.HTTP_200_OK)

def generate_df(queryset):
    df = queryset.to_dataframe()
    df = df.drop(['s_n','id'], axis=1)
    # df = df.set_index(['org','date'])
    result = df.to_json(orient='records', date_unit='ms', 
    lines=True).splitlines()
    return result

当我在交互式shell中运行上述代码时，它运行平稳，没有任何错误，但是当Django处理请求时，会弹出一个错误：'NoneType' object has no attribute 'to_json'

而且，JSON的格式并不像我所期望的那样是标准的。我在这里做错什么了？有人能解释吗？任何帮助都将不胜感激。

EDIT2:删除了get_queryset()方法，因为它在这里没有做任何事情。添加了用于检索数据帧的@action方法。

这里还有另一个问题，返回的JSON对象不是我最初提供给函数的查询集。过滤器集字段不能正常工作。每次我尝试获取特定的数据框架时，都会返回整个数据库的数据框架，而不是那个特定的查询。什么是最简单的解决方案？

编辑:添加堆栈跟踪：

AttributeError at /api/v1/stock/price/
'tuple' object has no attribute 'model'

Request Method: GET
Request URL: http://localhost:8000/api/v1/stock/price/?page=1
Django Version: 3.0
Python Executable: /home/anjaan/project/fintech/venv/bin/python
Python Version: 3.8.5
Python Path: ['/home/anjaan/project/fintech', '/usr/lib/python38.zip', '/usr/lib/python3.8', '/usr/lib/python3.8/lib-dynload', '/home/anjaan/project/fintech/venv/lib/python3.8/site-packages']
Server time: Wed, 17 Feb 2021 05:49:42 +0000
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'django.contrib.sites',
 'drf_yasg',
 'rest_framework',
 'rest_framework.authtoken',
 'rest_framework_swagger',
 'rest_framework_jwt',
 'rest_auth',
 'allauth',
 'allauth.account',
 'django_extensions',
 'django_rest_passwordreset',
 'django_filters',
 'channels',
 'users',
 'misc',
 'notification',
 'finance']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware',
 'fintech.middleware.UserAgentMiddleware',
 'fintech.middleware.UserActivityLogMiddleware']


Traceback (most recent call last):
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/django/core/handlers/base.py", line 115, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/django/core/handlers/base.py", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
    return view_func(*args, **kwargs)
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/rest_framework/viewsets.py", line 125, in view
    return self.dispatch(request, *args, **kwargs)
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/rest_framework/views.py", line 509, in dispatch
    response = self.handle_exception(exc)
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/rest_framework/views.py", line 469, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/rest_framework/views.py", line 480, in raise_uncaught_exception
    raise exc
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/rest_framework/views.py", line 506, in dispatch
    response = handler(request, *args, **kwargs)
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/rest_framework/mixins.py", line 38, in list
    queryset = self.filter_queryset(self.get_queryset())
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/rest_framework/generics.py", line 150, in filter_queryset
    queryset = backend().filter_queryset(self.request, queryset, self)
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/django_filters/rest_framework/backends.py", line 90, in filter_queryset
    filterset = self.get_filterset(request, queryset, view)
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/django_filters/rest_framework/backends.py", line 31, in get_filterset
    filterset_class = self.get_filterset_class(view, queryset)
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/django_filters/rest_framework/backends.py", line 73, in get_filterset_class
    class AutoFilterSet(self.filterset_base):
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/django_filters/rest_framework/backends.py", line 74, in AutoFilterSet
    class Meta(MetaBase):
  File "/home/anjaan/project/fintech/venv/lib/python3.8/site-packages/django_filters/rest_framework/backends.py", line 75, in Meta
    model = queryset.model

Exception Type: AttributeError at /api/v1/stock/price/
Exception Value: 'tuple' object has no attribute 'model'

Answer 1

你写：

df = df.set_index(['org','id'],inplace=True)

inplace=True意味着要对同一个对象进行更改，因此该方法不返回导致None存储在df中的任何内容。将该行更改为以下任一项：

df.set_index(['org','id'], inplace=True)

或

df = df.set_index(['org','id'])