How to convert a list in to queryset django

Question

I have a queryset(which is filtered actually) as below

posts = [, , , , 

        

Answer 1

The previous answers are correct if each list item already exists in the database, but sometimes this is not the case. In this case you can create a queryset stub based on the list and implement queryset-methods and queryset-properties as needed.

class ListAsQuerySet(list):

    def __init__(self, *args, model, **kwargs):
        self.model = model
        super().__init__(*args, **kwargs)

    def filter(self, *args, **kwargs):
        return self  # filter ignoring, but you can impl custom filter

    def order_by(self, *args, **kwargs):
        return self

qs = ListAsQuerySet(custom_list, model=Post)

Answer 2

Here's a simple util that you can run to produce a QS from a list:

def list_to_queryset(model, data):
    from django.db.models.base import ModelBase

    if not isinstance(model, ModelBase):
        raise ValueError(
            "%s must be Model" % model
        )
    if not isinstance(data, list):
        raise ValueError(
            "%s must be List Object" % data
        )

    pk_list = [obj.pk for obj in data]
    return model.objects.filter(pk__in=pk_list)

Answer 3

Actually i had found one way by googling, but this may take a lot of time for querying/generating results if there are huge number of records

custom_list = [rec.id for rec in posts if 'string_or_field' in rec.tags.all()]

querset = MyModel.objects.filter(id__in=custom_list)

Answer 4

You can query the Tag object first and filter Post with those ids:

tags = Tag.objects.filter(field_name='string_or_field')
posts = Post.objects.filter(tags__in=tags)