AttributeError: 'module' object has no attribute

问题

I have two python modules:

a.py

import b

def hello():
  print \"hello\"

print \"a.py\"
print hello()
print b.hi()

b.py

import a

def hi():
  print \"hi\"

When I run a.py, I get:

AttributeError: \'module\' object has no attribute \'hi\'

What does the error mean? How do I fix it?

回答1:

You have mutual top-level imports, which is almost always a bad idea.

If you really must have mutual imports in Python, the way to do it is to import them within a function:

# In b.py:
def cause_a_to_do_something():
    import a
    a.do_something()

Now a.py can safely do import b without causing problems.

(At first glance it might appear that cause_a_to_do_something() would be hugely inefficient because it does an import every time you call it, but in fact the import work only gets done the first time. The second and subsequent times you import a module, it's a quick operation.)

回答2:

I have also seen this error when inadvertently naming a module with the same name as one of the standard Python modules. E.g. I had a module called commands which is also a Python library module. This proved to be difficult to track down as it worked correctly on my local development environment but failed with the specified error when running on Google App Engine.

回答3:

The problem is the circular dependency between the modules. a imports b and b imports a. But one of them needs to be loaded first - in this case python ends up initializing module a before b and b.hi() doesn't exist yet when you try to access it in a.

回答4:

I got this error by referencing an enum which was imported in a wrong way, e.g.:

from package import MyEnumClass
# ...
# in some method:
return MyEnumClass.Member

Correct import:

from package.MyEnumClass import MyEnumClass

Hope that helps someone

回答5:

I experienced this error because the module was not actually imported. The code looked like this:

import a.b, a.c

# ...

something(a.b)
something(a.c)
something(a.d)  # My addition, which failed.

The last line resulted in an AttributeError. The cause was that I had failed to notice that the submodules of a (a.b and a.c) were explicitly imported, and assumed that the import statement actually imported a.

回答6:

All the above answers are great, but I'd like to chime in here. If you did not spot any issue mentioned above, try clear up your working environment. It worked for me.

回答7:

I ran into this problem when I checked out an older version of a repository from git. Git replaced my .py files, but left the untracked .pyc files. Since the .py files and .pyc files were out of sync, the import command in a .py file could not find the corresponding module in the .pyc files.

The solution was simply to delete the .pyc files, and let them be automatically regenerated.

回答8:

I faced the same issue. fixed by using reload.

import the_module_name
from importlib import reload
reload(the_module_name)

回答9:

on ubuntu 18.04 ( virtualenv, python.3.6.x), the following reload snippet solved the problem for me:

main.py

import my_module  # my_module.py
from importlib import reload # reload 
reload(my_module)

print(my_module)
print(my_modeule.hello())

where:

|--main.py    
|--my_module.py

for more documentation check : here

回答10:

Not sure how but the below change sorted my issue:

i was having the name of file and import name same for eg i had file name as emoji.py and i was trying to import emoji. But changing the name of file solved the issue .

Hope so it helps

回答11:

Circular imports cause problems, but Python has ways to mitigate it built-in.

The problem is when you run python a.py, it runs a.py but not mark it imported as a module. So in turn a.py -> imports module b -> imports module a -> imports module b. The last import a no-op since b is currently being imported and Python guards against that. And b is an empty module for now. So when it executes b.hi(), it can't find anything.

Note that the b.hi() that got executed is during a.py -> module b -> module a, not in a.py directly.

In your specific example, you can just run python -c 'import a' at top-level, so the first execution of a.py is registered as importing a module.

来源：https://stackoverflow.com/questions/1250103/attributeerror-module-object-has-no-attribute