无法导入名称 <MyClass> 在Python中

Question

I try to import a class in python but I get some trouble probably because of cyclic import but I don't know how to solve my problem.

The loop that appears in my traceback (packageA contains three files: A, B and C):

**In main.py**    
from packageA import fileA
**In fileA.py:**
from packageA import fileB    <- 
**In fileB.py:**
from packageA import fileC
**In fileC.py:**
from fileB import ClassB      <-

I get:

ImportError: cannot import name ClassB

At first, I thought that I could delete "import ClassB" from fileC as the whole fileB had already been imported before. But if I try so I get another error which is:

NameError: global name 'ClassB' is not defined

Can someone help?

Answer 1

This is a case of circular imports . fileB is importing fileC, which is importing fileB. The latter import is being satisfied with an empty, uninitialized module object.

In general, you do not want to use circular imports.