Question

I have a query set, categories = unipart.categories.all(), which is all the categories that a unipart object is linked to.

However, I’d like to remove the top-level categories from this list — ie. those with subcategories that the unipart is also listed within.

Or those categories with a parent_id equal to one of the category_ids in the queryset.

For example if a unipart was listed in:
Nutmeg (parent= Spices) and
Spices (parent = Food)

then I’d want to ONLY include Nutmeg — so basically I want to ‘pop’ Spices from the queryset.

What is the best way to do this? I would rather not use a list.

Here’s my models:

class UniPart (models.Model):
categories=models.ManyToManyField(Category, related_name = 'unipart')

class Category (MPTTModel):
    category = models.CharField(max_length=250)
    oc_id= models.IntegerField()
    parent = TreeForeignKey('self', blank=True, null=True, related_name='children')
    def __unicode__(self):

Answer 1

Your can exclude those categories who has a child category binded to this unipart item:

categories = unipart.categories.exclude(
                 categorieschild__unipart = unipart).distinct()

Here categorieschild is de related name for the categories children.