从多对多模型获取值列表

Question

I would like to retrieve a list of values on the format ['BMW', 'Mercedes', 'Audi'] (these are the three selected out from a list of 50+ different car makes made in a multiple select form field/list.

Values exist in a ManyToMany:

class CarMakeModel(models.Model):
    Make = models.CharField(max_length=30)

class Product(models.Model):
    selection = models.ManyToManyField(CarMakeModel)

Now I would like to retrieve the selection made, eg in the shell:

select = product.models.Product.objects.latest('id').selection.values('Make')

This will return:

<QuerySet [{'Make': 'BMW'}, {'Make': 'Mercedes'}, 'Make': 'Audi'}]

How do I get this QuerySet reply into this format ['BMW', 'Mercedes', 'Audi'] ?

I have tried list(select) and tuple(select) which returns:

[{'Make': 'BMW'}, {'Make': 'Mercedes'}, 'Make': 'Audi'}]

and

({'Make': 'BMW'}, {'Make': 'Mercedes'}, 'Make': 'Audi'})

but already now it feels I have taken too many steps for a seemingly simple request. My question is how do I more correct achieve my aim?

Answer 1

您可以改用values_list方法：

select = product.models.Product.objects.latest('id').selection.values_list('Make', flat=True)