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Editorial Team
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Asked: 2026-05-14T03:24:53+00:00

Say I have a model object ‘Person’ defined, which has a field called ‘Name’.

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Say I have a model object ‘Person’ defined, which has a field called ‘Name’. And I have a list of people:

l = ['Bob','Dave','Jane']

I would like to return a list of all Person records where the first name is not in the list of names defined in l.

What is the most pythonic way of doing this?

EDIT: After thinking about it, what I really was trying to do is come up with a sub list of l that wasn’t present in the Person table. Is there an efficient way of doing this? I can think of a few ways, not sure how efficient though.

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1 Answer

  1. Editorial Team

    Renaming l for readability:

    names = ['Bob','Dave','Jane']

Person.objects.[exclude][1](Name__[in][2]=names)

    UPDATE 1: Answer to the second question (in your ‘EDIT’ paragraph):

    present = Person.objects.values_list('Name', flat=True)
absent = set(names) - set(present)   
# or, if you prefer named functions to the set operator '-'
absent = set(names).difference(present)

    Yes, the “right hand side” of difference (but not ‘-‘) accepts any iterable (I had to look it up to confirm).

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