Count # of non-empty fields in Django

Question

I'm trying to make a site where people can create an event, then add pictures (from an outside album, no need to upload), and then I want to pull info about how many pictures are added and display that on a central catalog. For example (excluding some code for brevity's sake):

models.py

class EventDB(models.Model):
     picture1 = models.CharField ("picture 1", max_length=255, blank=True)
     picture2 = models.CharField ("picture 2", max_length=255, blank=True)

If someone added an item to EventDB and added 1 picture, I could return the output as 1. If they added 2 pictures, it would return as 2, and so on and so forth.

I want to have a central page that lists all the events and has the corresponding number of pictures next to it. For example:

Event1 (2)

Event2 (1)

Event3 (4)

where the number in parenthesis is the # of pictures. What would be the best way to do this? I've tried playing around with (picture1__isnull=True).count() but that counts the TOTAL number of items in my DB without a picture1 uploaded.

Thanks!!

Answer 1

Add a property or a function that will count the total number of pictures for you:

class EventDB(models.Model):
    picture1 = models.CharField ("picture 1", max_length=255, blank=True)  
    picture2 = models.CharField ("picture 2", max_length=255, blank=True)

    def picture_count(self):
        fields = self._meta.get_fields()
        n_count = len([ x for x in fields if getattr(self, field.name) ])
        return n_count    

Alternatively you can write an F function that will do the annotation for you in the database. The syntax of the function will vary based on your database.