Make calculations for records inside pagination, django-CodePudding

I want to calculate the sum of two records but only inside the pagination.

class MacaListView(ListView):
    model = Maca
    paginate_by = 20

        def get_context_data(self, *, object_list=None, **kwargs):
            context = super(MacaListView, self).get_context_data(object_list=None, **kwargs)
            maca = Maca.objects.all()
            for i in range(0, maca.count()):
                maca1 = Maca.objects.get(maca[i].id)
                maca1.number = maca.number   1

                maca1.save()

This will go to every single record and do the logic. I want the logic to be executed for only records in pagination (do calculate for only 20 records)

CodePudding user response：

Could you please try it? in here we get the current page number and slice queryset to get only needed elements.

class MacaListView(ListView):
    model = Maca
    paginate_by = 20

        def get_context_data(self, *, object_list=None, **kwargs):

            context = super(MacaListView, self).get_context_data(object_list=None, **kwargs)
            page =  int(self.request.GET.get('page', 1))
            maca = Maca.objects.all()[(page-1)*self.paginate_by:self.paginate_by]
            for i in range(0, maca.count()):
                maca = Maca.objects.get(maca[i].id)
                maca.number = maca.number   1

                maca.save()