Filtering tags in M2M Field Django

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So I have my models

Class Category((models.Model)
    category = models.CharField()

class Group(models.Model)
    Title = models.CharField()
    category = models.ManyToManyField(Category, related_name= tags)

So I want to be able to filter all the groups with similar tags to the group currently in view

In my views.py I tried

group = Group.objects.get(id=pk)
groups = Group.objects.filter(category=group.category)

But that doesn't work

django-templates django-forms django-views django-models django
1 Answers

You can retrieve all the groups that have at least one Category in common with:

Group.objects.filter(category__in=group.category.all()).distinct()

The .distinct() call [Django-doc] prevents listing a Group that many times as there are matching categorys.

Another option is to use the relation in reverse, and thus work with:

Group.objects.filter(category__tags=group).distinct()

The related name however does not make much sense: the related_name=… parameter [Django-doc] is the name of the relation in reverse, related_name='groups' thus makes more sense. In that case we query with:

Group.objects.filter(category__groups=group).distinct()
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