Get all related many-to-many objects from a Django QuerySet?

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I have a twisty maze of interrelated Django models, with many-to-many fields describing the relationships. What's the cleanest way to get a list of unique members of a related model from a QuerySet? If I have a Item model with a groups ManyToMany pointing to the Groups model.

If I have a queryset of Items, of 'items', how do I get this: groups = items0.groups.all(). Values_list('name', flat=True) But for the whole set? Do I need to iterate through them all and do set().intersect()?

Python django many-to-many django-queryset link|improve this question asked Jan 28 '11 at 0:38samurailawngnome235110 67% accept rate.

One solution is to use 2 queries. You can use the reverse relationships to query all Groups that an Item in your items points to. Groups = groups.objects.

Filter(item__in=items).distinct(). Values_list('name', flat=True).

Sufficiently elegant. Thanks. – samurailawngnome Jan 28 '11 at 0:59 You may also find it useful to use flat=True as a parameter to values_list, which will return the result as a list of names, rather than a list of tuples of names.

– gorus Jan 30 '11 at 23:01 @gorus -- updated. I'm finding it funny I removed flat from the original post because I got it confused with distinct. – Yuji Tomita Jan 30 '11 at 23:31.

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