CODEWITHSUNDEEP
pythondjangodjango-orm
jabs
jabs

Reputation: 1848

counting queryset returns 'list' object has no attribute 'id'

I have a model with a manytomany column. I want to limit the number of groups a user can submit.

Here is what I'm doing

        group_name = [g.id for g in form.cleaned_data['groups']]
        gr=group_name.id.count()
        if gr>3:
            raise forms.ValidationError("you can only add 3 groups")
        return group_name

the error is:

 Exception Value: 'list' object has no attribute 'id'

I can't seem to find what I'm doing wrong. Thanks.

Upvotes: 0

Views: 2180

Answers (3)

monkut
monkut

Reputation: 43840

You're creating a list object, so standard list operations work.

group_name_ids = [g.id for g in form.cleaned_data['groups']]
group_id_count = len(group_name_ids)

It seems that "groups" here is a list of model objects, so you could get the count via:

group_count = len(form.cleaned_data["groups"])

However, since your returning the resulting built group_name_ids list, you might as well just get the len() of that.

Upvotes: 2

namit
namit

Reputation: 6957

>>> nk=['city1','city2','city1','city3','city1']
>>> from collections import Counter
>>> mycount=Counter()
>>> for word in nk:
...     mycount[word]+=1
...     
>>> mycount['city1']
3
>>>

refer python documentaion http://docs.python.org/library/collections.html

Upvotes: 0

Yevgen Yampolskiy
Yevgen Yampolskiy

Reputation: 7198

group_name is a list, and group_name.id cannot be resolved :)

Upvotes: 0

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