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djangomany-to-manyintersectiondjango-queryset
veered
veered

Reputation: 638

Django Querying Question

If I were to have two different QuerySets in Django, both representing a ManyToMany relation with the same model, how would I find the intersections?

Upvotes: 2

Views: 212

Answers (3)

mlissner
mlissner

Reputation: 18166

You might be able to avoid the question by using the IN operator to create a subquery: http://docs.djangoproject.com/en/dev/ref/models/querysets/#in

Upvotes: 1

Yaroslav
Yaroslav

Reputation: 2736

  1. order querysets by same set of keys
  2. call iterator() on both querysets
  3. feed iterators to intersect function from this answer: Joining a set of ordered-integer yielding Python iterators

Upvotes: 0

Pierre-Jean Coudert
Pierre-Jean Coudert

Reputation: 9347

Merge your querysets in a list and next, create a set, you'll convert back to a list :

from itertools import chain
merged_qs = chain(queryset1, queryset2) 
intersection_list = list(set(list( merged_qs )))

Upvotes: 0

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