Unable to obtain c.poll

[Smaran Harihar]

Hi Djangoers,

I am almost completing my first tutorial but got stuck at the last point. So I am assigning Choice object to 'c',

c = p.choice_set.filter(choice_text__startswith='Just')

And I am getting this output when I check 'c'

[<Choice: Just Hacking again>]

And I am also getting the right output for 'p'

<Poll: WASSUP!!!!>

But when I am executing,

 c.poll

This is my output,

Traceback (most recent call last):

  File "<console>", line 1, in <module>

AttributeError: 'QuerySet' object has no attribute 'poll'

Not sure where I am going wrong?

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Thanks & Regards

Smaran Harihar

[Daniel Roseman]

You're not assigning a Choice object to `c`. You're assigning a queryset (basically, a list) of one Choice objects to c - hence the square brackets when you print it. As the documentation explains, `filter` *always* returns a queryset, even if only one object matches.

You can do c[0] to get the Choice object, or use `get()` instead of `filter()` (although note that will raise an exception if zero or > 1 objects match).

--

DR.

[Smaran Harihar]

Thanks DR. Now I understand the difference between filter and get.

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[Smaran Harihar]

Also when we are taking,

 c = p.choice_set.filter(choice_text__startswith='Just hacking')
>>> c.delete()

Are we deleting the object or just that filter queryset choice? 

On Mon, Jul 2, 2012 at 1:02 PM, Daniel Roseman <dan...@roseman.org.uk> wrote:

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[Melvyn Sopacua]

On 2-7-2012 23:37, Smaran Harihar wrote:
> Also when we are taking,
>
> c = p.choice_set.filter(choice_text__startswith='Just hacking')>>> c.delete()
>
>
> Are we deleting the object or just that filter queryset choice?

The list returned by the filter.
c = p.choice_set.get(..)
c.delete() # calls the delete method of the choice object

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Melvyn Sopacua