Django: __in query lookup doesn't maintain the order in queryset

Question

I have ID\'s in a specific order

>>> album_ids = [24, 15, 25, 19, 11, 26, 27, 28]
>>> albums = Album.objects.filter( id__in=album_ids, publi         


        

Answer 1

You can't do it in django via ORM. But it's quite simple to implement by youself:

album_ids = [24, 15, 25, 19, 11, 26, 27, 28]
albums = Album.objects.filter(published=True).in_bulk(album_ids) # this gives us a dict by ID
sorted_albums = [albums[id] for id in albums_ids if id in albums]

Answer 2

You can do it in Django via ORM using the extra QuerySet modifier

>>> album_ids = [24, 15, 25, 19, 11, 26, 27, 28]
>>> albums = Album.objects.filter( id__in=album_ids, published= True
             ).extra(select={'manual': 'FIELD(id,%s)' % ','.join(map(str, album_ids))},
                     order_by=['manual'])

Answer 3

Assuming the list of IDs isn't too large, you could convert the QS to a list and sort it in Python:

album_list = list(albums)
album_list.sort(key=lambda album: album_ids.index(album.id))

Answer 4

If you use MySQL and want to preserve the order by using a string column.

words = ['I', 'am', 'a', 'human']
ordering = 'FIELD(`word`, %s)' % ','.join(str('%s') for word in words)
queryset = ModelObejectWord.objects.filter(word__in=tuple(words)).extra(
                            select={'ordering': ordering}, select_params=words, order_by=('ordering',))