如何获取 Django 模型字段对象的值

Question

I got a model field object using field_object = MyModel._meta.get_field(field_name) . How can I get the value (content) of the field object?

Answer 1

Use value_from_object :

field_name = 'name'
obj = MyModel.objects.first()
field_object = MyModel._meta.get_field(field_name)
field_value = field_object.value_from_object(obj)

Which is the same as getattr :

field_name = 'name'
obj = MyModel.objects.first()
field_object = MyModel._meta.get_field(field_name)
field_value = getattr(obj, field_object.attname)

Or if you know the field name and just want to get value using field name, you do not need to retrieve field object firstly:

field_name = 'name'
obj = MyModel.objects.first()
field_value = getattr(obj, field_name)

Answer 2

Assuming you have a model as,

class SampleModel(models.Model):
    name = models.CharField(max_length=120)

Then you will get the value of name field of model instance by,

sample_instance = SampleModel.objects.get(id=1)
value_of_name = sample_instance.name

Answer 3

If you want to access it somewhere outside the model You can get it after making an object the Model. Using like this

OUSIDE THE MODEL CLAA :

myModal = MyModel.objects.all()

print(myModel.field_object)

USING INSIDE MODEL CLASS
If you're using it inside class you can simply get it like this

print(self.field_object)

Answer 4

Here is another solution to return the nth field of a model where all you know is the Model's name. In the below solution the [1] field is the field after pk/id.

model_obj = Model.objects.get(pk=pk)
field_name = model_obj._meta.fields[1].name
object_field_value = getattr(model_obj, field_name)