Python Import Looping issues

When invoking a function in Django, an error occurs:

can‘timport get_user_info

found that the import of this module Ah, why the import is not successful?　The issue of importing loops is the tip of the person. Open the "Python core programming" module of the import cycle that chapter, see To understand.

Simulate a simple scene

There is a function a () in a.py, which calls for function B () in b.py, and the function C () in b.py needs to call a (), which is a circular import. The code looks like this:

from  b import  bprint   '--- ------This is module a.py----------'  def  a   () :  print  Span class= "hljs-string" > "Hello, a"  B () A ()  

fromimport aprint‘----------this is module b.py----------‘def b():    print"hello, b"def c():    a()c()

Run: Python a.py, error is as follows:

Zy@zy: ~/code/python/test/import$ Python a.pyTraceback(most recent):  File "a.py", line1,inch< module>From B Import BFile "/home/zy/code/python/test/import/b.py", line1,inch< module>From a import aFile "/home/zy/code/python/test/import/a.py", line1,inch< module>From B Import BImporterror:Cannot import name b

In the a.py import b.b (), in the import of B file, but also to import a file, a file to import B file, this is a dead loop, nature is not allowed.

Workaround:

• You can place the statements of the import module in a local (function). As shown below:

print   '---------This is module a.py----------'  def  Span class= "Hljs-title" >a   () :  print   "Hello, a"  from  b import  b b () A ()  

‘----------this is module b.py----------‘def b():    print"hello, b"def c():    fromimport a    a()c()

Run: Python a.py, the results are as follows:

zy@zy:~/code/python/test/import$ module a.py----------module b.py----------module a.py----------hello, ahello, bhello, ahello, bhello, b

Python Import Looping issues