Django: UnboundLocalError: local variable 'company' referenced before assignment

问题

I am trying to make a url field in my detail view by passing two primary key in it...

This is what I have done in urls.py:

    url(r'^company/(?P<pk1>\d+)/groupdetail/(?P<pk2>\d+)/$',views.group1DetailView.as_view(),name='groupdetail'),

And in my views:

    def get_object(self):
        pk1 = self.kwargs['pk1']
        pk2 = self.kwargs['pk2']
        company = get_object_or_404(company, pk=pk1)
        group1 = get_object_or_404(group1, pk=pk2)
        return group1

I am getting error in this line:

company = get_object_or_404(company, pk=pk1)

And in my group1 list view I have done this:

<a href="{% url 'accounting_double_entry:groupdetail' pk1=company_details.pk pk2=group1_details.pk %}">{{group1.group_Name}}</a>

Can anyone tell me what I am doing wrong in this code?

Thank you

回答1:

In your function, you assign to a variable named company, so Python considers company to be a local variable, but at that moment unassigned, so you will need to use anoter variable name to avoid this:

def get_object(self):
    pk1 = self.kwargs['pk1']
    pk2 = self.kwargs['pk2']
    # make sure the variable name is different than the model name
    company_obj = get_object_or_404(company, pk=pk1)
    group1 = get_object_or_404(group1, pk=pk2)
    return group1

Since you here however do not use company_obj, you might want to drop the variable name:

def get_object(self):
    pk1 = self.kwargs['pk1']
    pk2 = self.kwargs['pk2']
    get_object_or_404(company, pk=pk1)
    group1 = get_object_or_404(group1, pk=pk2)
    return group1

as an alternative, if your group1 is "related" to company, and you want to chekck if that holds, it makes sense to filter on that company:

def get_object(self):
    pk1 = self.kwargs['pk1']
    pk2 = self.kwargs['pk2']
    company_obj = get_object_or_404(company, pk=pk1)
    group1 = get_object_or_404(group1, pk=pk2, company=company_obj)
    return group1

Note: PEP-8 [Python-doc] advices class names to be written in CamelCase, whereas fields and local variables are written in lower_case. It is not uncommon to see something like some_class = SomeClass(), so because the camel case starts with an uppercase, clashes between local variables and classes, will never exist.

来源：https://stackoverflow.com/questions/52603288/django-unboundlocalerror-local-variable-company-referenced-before-assignment