[python] Default value for field in Django model

Suppose I have a model:

class SomeModel(models.Model):
    id = models.AutoField(primary_key=True)
    a = models.CharField(max_length=10)
    b = models.CharField(max_length=7)

Currently I am using the default admin to create/edit objects of this type. How do I remove the field b from the admin so that each object cannot be created with a value, and rather will receive a default value of 0000000?

You can also use a callable in the default field, such as:

b = models.CharField(max_length=7, default=foo)

And then define the callable:

def foo():
    return 'bar'

You can set the default like this:

b = models.CharField(max_length=7,default="foobar")

and then you can hide the field with your model's Admin class like this:

class SomeModelAdmin(admin.ModelAdmin):
    exclude = ("b")