[Answer]-Django: How to filter out sub elements

Easiest and most efficient way is to filter first:

blog.entry_set.filter(published=True)

Or, you can simply use an if statement:

if entry.published:
    print entry

for o in queryset:
    if not results.has_key(o.name):
       results[o.name] = list()
    if not (...check if Z):
       results[o.name].append(o)

for a in results:
    print a
    for b in results[a]:
        print b.state

Suppose you have models:

class Blog(models.Model):
    name = models.CharField(max_length=100)
    tagline = models.TextField()

    def __unicode__(self):
        return self.name

class Author(models.Model):
    name = models.CharField(max_length=50)
    email = models.EmailField()

    def __unicode__(self):
        return self.name

class Entry(models.Model):
    blog = models.ForeignKey(Blog)
    headline = models.CharField(max_length=255)
    body_text = models.TextField()
    pub_date = models.DateTimeField()
    mod_date = models.DateTimeField()
    authors = models.ManyToManyField(Author)
    n_comments = models.IntegerField()
    n_pingbacks = models.IntegerField()
    rating = models.IntegerField()

    def __unicode__(self):
        return self.headline

and you want to exclude all blogs that have name “test”

You would run the code:

Entry.objects.exclude(blog__name=’test’)

and it would write query:

SELECT ... FROM `entry` INNER JOIN `blog` ON (`entry`.`blog_id` = `blog`.`id`) WHERE NOT (`blog`.`name` = test )

aobjs = [b.a for b in B.objects.exclude(state='Z')]

Or

aobj.b_set.exclude(state='Z')

Change Blog.objects.all() with Blog.objects.filter(entry__published=True)

That should do the trick!