尝试运行 Python 脚本时出现“ImportError: No module named”

Question

I'm trying to run a script that launches, amongst other things, a python script. I get a ImportError: No module named..., however, if I launch ipython and import the same module in the same way through the interpreter, the module is accepted.

What's going on, and how can I fix it? I've tried to understand how python uses PYTHONPATH but I'm thoroughly confused. Any help would greatly appreciated.

Answer 1

This issue arises due to the ways in which the command line IPython interpreter uses your current path vs. the way a separate process does (be it an IPython notebook, external process, etc). IPython will look for modules to import that are not only found in your sys.path, but also on your current working directory. When starting an interpreter from the command line, the current directory you're operating in is the same one you started ipython in. If you run

import os os.getcwd()

you'll see this is true.

However, let's say you're using an ipython notebook, run os.getcwd() and your current working directory is instead the folder in which you told the notebook to operate from in your ipython_notebook_config.py file (typically using the c.NotebookManager.notebook_dir setting).

The solution is to provide the python interpreter with the path-to-your-module. The simplest solution is to append that path to your sys.path list. In your notebook, first try:

 import sys sys.path.append('my/path/to/module/folder') import module_of_interest

If that doesn't work, you've got a different problem on your hands unrelated to path-to-import and you should provide more info about your problem.

The better (and more permanent) way to solve this is to set your PYTHONPATH , which provides the interpreter with additional directories look in for python packages/modules. Editing or setting the PYTHONPATH as a global var is os dependent, and is discussed in detail here for Unix or Windows .

Answer 2

Just create an empty python file with the name __init__.py under the folder which showing error, while you running the python project.

Answer 3

Make sure they are both using the same interpreter. This happened to me on Ubuntu:

 $ ipython3 -c 'import sys; print(sys.version)' 3.4.2 (default, Jun 19 2015, 11:34:49) \n[GCC 4.9.1] $ python3 -c 'import sys; print(sys.version)' 3.3.0 (default, Nov 27 2012, 12:11:06) \n[GCC 4.6.3]

And sys.path was different between the two interpreters. To fix it, I removed Python 3.3.

Answer 4

The main reason is the sys.paths of Python and IPython are different.

Please refer to lucypark link, the solution works in my case. It happen when install opencv by

conda install opencv

And got import error in iPython, There are three steps to solve this issue:

import cv2
ImportError: ...

1. Check path in Python and iPython with following command

import sys
sys.path

You will find different result from Python and Jupyter. Second step, just use sys.path.append to fix the missed path by try-and-error.

2. Temporary solution

In iPython:

import sys
sys.path.append('/home/osboxes/miniconda2/lib/python2.7/site-packages')
import cv2

the ImportError:.. issue solved

3. Permanent solution

Create an iPython profile and set initial append:

In bash shell:

ipython profile create
... CHECK the path prompted , and edit the prompted config file like my case
vi /home/osboxes/.ipython/profile_default/ipython_kernel_config.py

In vi, append to the file:

c.InteractiveShellApp.exec_lines = [
 'import sys; sys.path.append("/home/osboxes/miniconda2/lib/python2.7/site-packages")'
]

DONE

Answer 5

Doing sys.path.append('my-path-to-module-folder') will work, but to avoid having to do this in IPython every time you want to use the module, you can add export PYTHONPATH="my-path-to-module-folder:$PYTHONPATH" to your ~/.bash_profile file.

Answer 6

This is how I fixed it:

 import os import sys module_path = os.path.abspath(os.getcwd() + '\\..') if module_path not in sys.path: sys.path.append(module_path)

Answer 7

Before installing ipython, I installed modules through easy_install; say sudo easy_install mechanize .

After installing ipython, I had to re-run easy_install for ipython to recognize the modules.

Answer 8

If you are running it from command line, sometimes python interpreter is not aware of the path where to look for modules.

Below is the directory structure of my project:

 /project/apps/.. /project/tests/..

I was running below command:

 >> cd project >> python tests/my_test.py

After running above command i got below error

no module named lib

lib was imported in my_test.py

i printed sys.path and figured out that path of project i am working on is not available in sys.path list

i added below code at the start of my script my_test.py .

 import sys import os module_path = os.path.abspath(os.getcwd()) if module_path not in sys.path: sys.path.append(module_path)

I am not sure if it is a good way of solving it but yeah it did work for me.

Answer 9

I have found that the solution to this problem was extensively documented here:

https://jakevdp.github.io/blog/2017/12/05/installing-python-packages-from-jupyter/

Basically, you must install the packages within the Jupyter environment, issuing shell commands like:

 .{sys executable} -m pip install numpy

Please check the above link for an authoritative full answer.

Answer 10

This kind of errors occurs most probably due to python version conflicts. For example, if your application runs only on python 3 and you got python 2 as well, then it's better to specify which version to use. For example use

python3.....

instead of

python

Answer 11

Had a similar problem, fixed it by calling python3 instead of python , my modules were in Python3.5.

Answer 12

I found yet another source of this discrepancy:

I have ipython installed both locally and in commonly in virtualenvs. My problem was that, inside a newly made virtualenv with ipython, the system ipython was picked up, which was a different version than the python and ipython in the virtualenv (a 2.7.x vs. a 3.5.x), and hilarity ensued.

I think the smart thing to do whenever installing something that will have a binary in yourvirtualenv/bin is to immediately run rehash or similar for whatever shell you are using so that the correct python/ipython gets picked up. (Gotta check if there are suitable pip post-install hooks...)

Answer 13

Solution without scripting:

1. Open Spyder -> Tools -> PYTHONPATH manager
2. Add Python paths by clicking "Add Path". Eg: 'C:\Users\User\AppData\Local\Programs\Python\Python37\Lib\site-packages'
3. Click "Synchronize..." to allow other programs (eg Jupyter Notebook) use the pythonpaths set in step 2.
4. Restart Jupyter if it is open

Answer 14

This is probably caused by different python versions installed on your system , ie python2 or python3 .

Run command $ pip --version and $ pip3 --version to check which pip is from at Python 3x . Eg you should see version information like below:

 pip 19.0.3 from /usr/local/lib/python3.7/site-packages/pip (python 3.7)

Then run the example.py script with below command

$ python3 example.py

Answer 15

Happened to me with the directory utils . I was trying to import this directory as:

 from utils import somefile

utils is already a package in python. Just change your directory name to something different and it should work just fine.

Answer 16

This answer applies to this question if

1. You don't want to change your code
2. You don't want to change PYTHONPATH permanently

Temporarily modify PYTHONPATH

path below can be relative

PYTHONPATH=/path/to/dir python script.py

Answer 17

 import sys sys.path.append('/Users/{user}/Library/Python/3.7/lib/python/site-packages') import ta

Answer 18

If anyone comes across this issue using conda with Jupyter Notebook in MSVS Code, the solution is to make sure you're using the correct kernel. The kernel is in a box in the top right corner of the interface and looks like this:

I pointed mine to the version of Python that also matched my application path -- problem solved

Answer 19

This problem occurs due to the different versioning - eg if the Python installed on your machine is installed in a folder called path_to_lib/python3.6 but your notebook is running in Python 3 - the spacing in the naming matters

How to solve it?

When creating a new jupyter notebook, just choose the Python with the same versioning as yours (watch out for spaces.). See the attached image

Answer 20

This is what worked for me: I just changed my working directory inside my notebook

import os os.chdir("my/path/to/module") os.getcwd()

Answer 21

I have a similar issued with my Jupyter Lab setup which I resolved by checking the Jupyter Lab log on opening. This informed me that the virtual environment (pipenv) couldn't locate the Jupyter Lab so it used a shared version (from an earlier installation of Python).

I created a requirements.txt and discovered I hadn't installed Jupyter Lab in this new environment. Installing it resolved the import error.

Answer 22

Remove pathlib and reinstall it. Delete the pathlib in sitepackages folder and reinstall the pathlib package by using pip command:

 pip install pathlib