python import error, seems like recursive import, but can not resolve by such way

Question

Updated Problem solved, I have some design problem here.

The directory looks like that:

/view
  |-__init__.py
  |-quiz.py
  |-test.py
  |-user.py

And the problem is that in quiz.py, I import a class from test. and in test.py, I import a class from quiz .

Updated: I changed import but there is still a AttributeError

The code as following:

quiz.py

#ignore some imports here
import test
from user import User

class Quiz(Document):
    creator         =   ReferenceField(User, reverse_delete_rule=CASCADE)
    info            =   GenericEmbeddedDocumentField("QuizInfo")
    description     =   StringField(max_length=100)
    attachment      =   GenericEmbeddedDocumentField("QuizAttach")
    correctanswer   =   GenericEmbeddedDocumentField("QuizAnswer")
    wronganswer     =   GenericEmbeddedDocumentField("QuizAnswer")
    manualdifficulty=   FloatField(min_value=0, max_value=1)
    autodifficulty  =   FloatField(min_value=0, max_value=1)
    checkout        =   GenericEmbeddedDocumentField("QuizCheckcout")
    tag             =   ListField(StringField(max_length=20))

#ignore some codes here

class QuizCheckout(EmbeddedDocument):
    time            =   DateTimeField()
    type            =   IntField()
    description     =   StringField()
    test            =   ReferenceField(test.Test, reverse_delete_rule=CASCADE)

test.py

import quiz


class Test(Document):
    createdate      =   DateTimeField()             #Create datetime
    description     =   StringField()               #decription of this test
    takennumber     =   IntField()                  #the number of students who may take this test
    quiz            =   GenericEmbeddedDocumentField('TestQuiz')

class TestQuiz(EmbeddedDocument):
    quiz            =   ListField(ReferenceField(quiz.Quiz, reverse_delete_rule=CASCADE))
                        #Reference to Quiz, if Quiz is deleted, this reference will be deleted too.
    correct         =   IntField()
                        #how many students got this right

and the error is

Exception Type: AttributeError Exception
Value: 'module' object has no attribute 'Quiz'

At first I thought that maybe a recursive problem, but I only find that I could move import into functions to avoid recursive import, but there is no functions here, and I try to move import into class, it don't work.

Is there any way to keep these definition in separate file?

possible duplicate of [Circular (or cyclic) imports in Python](http://stackoverflow.com/questions/744373/circular-or-cyclic-imports-in-python) — simonzack, Jul 26 '14 at 08:06

score 3 · Answer 1 · edited May 23 '17 at 11:58

3

This is a classical cyclic import situation. Instead of using "from test import Test", you can simply "import test" and then access Test by test.Test. For more info see this stackoverflow question.

edited May 23 '17 at 11:58

Community

1
1

answered Mar 30 '12 at 10:24

hymloth

6,869
5
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I changed it and there is another error here. `Exception Type: AttributeError Exception Value: 'module' object has no attribute 'Quiz'` – bxshi Mar 30 '12 at 10:31
1

@bxshi Also change `from quiz import Quiz` to `import quiz` – Janne Karila Mar 30 '12 at 10:40
@JanneKarila yes, I change `from quiz import Quiz` to `import quiz`, and change `from test import Test` to `import test`, and it comes out a `AttributeError` – bxshi Mar 30 '12 at 10:43

score 1 · Accepted Answer · answered Mar 30 '12 at 10:56

1

Move QuizCheckout to a separate module. (QuizCheckout references Test at the class definition level, and Test references Quiz, that is the root of the problem)

answered Mar 30 '12 at 10:56

Janne Karila

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yes, thanks! Already found that. I should use `ListField(ReferenceField())` instead. – bxshi Mar 30 '12 at 11:21

score 0 · Answer 3 · answered Mar 30 '12 at 10:28

0

If what hymloth writes is correct (I did not try it out) you should also be able to use the name "Test" again by doing this:

import test
Test = test.Test

answered Mar 30 '12 at 10:28

katzenversteher

810
6
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yeah, but with his instruction, there comes another error, it told me that `module object has no attribute 'Quiz'` how is that? Did some other configure should be done? – bxshi Mar 30 '12 at 10:36
You could start the debugger after the import by inserting this: "import pdb; pdb.set_trace()" and then once the breakpoint is triggered you can do "dir(Quiz)" to check what's going on. Hope it works! – katzenversteher Mar 30 '12 at 10:55

python import error, seems like recursive import, but can not resolve by such way

3 Answers3