I want to store a list of integers as a field in my model. As there is no field provided for this by default in Django, I am doing it by using a CommaSeparatedIntegerField called `x`. In my view, I then take this string and create a list of integers from it. When a model instance is created with parameter `n`, I want `x` to be set to length `n`, with each element being set to zero.

Here's the model:

```
class Foo(models.Model):
    id = models.IntegerField(default = 0)
    x = models.CommaSeparatedIntegerField(max_length = 10)

@classmethod
def create(cls, _id, n):
    user = cls(id = _id)
    user.class_num_shown = '0,' * n

```

Then I create an instance:

```
f = Foo.create(1, 4)
f.save()

```

And load it from the database and convert the string into a list:

```
f = Foo.objects.get(id = 1)
x_string = f.x
x_list = x_string.split(',')
print x_list

```

But this outputs `[u'0,0,0,0,']` rather than what I want, which would be `[0,0,0,0]`. How can I achieve my desired output?