Python结合FOR循环和IF语句

Question

I have some issues with this small piece of code:

for key in UserInput.objects.all():
        if UserInput.category_id == 2:
            data = {}
            data['label'] = key.input_date
            data['value'] = key.input_value
            dataSource['data'].append(data)

I just don't seem to get it working. The only thing I want to do is to retrieve all rows from the UserInput table which have a category_id of 2 and then execute the four data lines for each row to use in my bar chart.

I get a variety of errors. I get an Object of type date is not JSON serializable on data['label'] = key.input_date. If I replace input_date with another (string) value, my bar chart seems to work, but it shows an empty bar chart. I tried to serialize my input_date, but I get even more errors when I try to do that.

json_data = serializers.serialize("xml", UserInput.objects.all())

and

fields = ['input_date']
    qs = UserInput.objects.all()
    json_input_data = serializers.serialize('json', qs, fields=fields)

My Python knowledge doesn't reach far enough to solve this on my own.

I would prefer to sort the data to month-year instead of day-month-year, but I would understand if this is beyond the scope of my question

EDIT: As many pointed it out in the comments, I do indeed use Django. I didn't mention it before because I thought it wouldn't be relevant.

Answer 1

Seems like you are using Django, so you should use the tools provided by Django .

objects_with_category_id_2 = UserInput.objects.filter(category_id=2)
for obj in objects_with_category_id_2:
     data =  {'label': obj.input_date,
              'value': obj.input_value}
     dataSource['data'].append(data)