"ImportError: No module named" when trying to run Python script

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.

You need to give more information. When you say "run a script", do you mean a shell script? What module is it that you cannot import? Where is that module located? Where is your script located? — BrenBarn, Mar 20 '13 at 03:11
If you want a definitive answer to "what's going on", start python with the `-v` option and you will see where python is (or is not) finding the modules you import. — FatalError, Mar 20 '13 at 03:13
What are you trying to import? Are the two python scripts in the same directory? — pynovice, Mar 20 '13 at 03:50
What operating system are you using? How did you install python? How did you install ipython? — Warren Weckesser, Mar 20 '13 at 04:25
Please give us the code you are running, the full text of the stack trace, and the exact steps you are taking to produce the error. It's rather difficult to assist when we don't know what the exact problem is. — MattDMo, Mar 20 '13 at 04:49
I guess it's a problem lots of users experience, even 4 years after the question was first asked. — CodeOcelot, Jun 15 '17 at 20:10

tyleha · Accepted Answer · 2021-08-24T19:10:07.113

241

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.

edited Aug 24 '21 at 19:10

answered Mar 25 '13 at 18:24

tyleha

3,319
1
17
25

2

PSA: if you've come to this SO question because you're getting this error in jupyter-notebook, then see below, https://stackoverflow.com/a/27944947/127971 Unfortunately, the question is not specific enough for a single answer. – michael Jul 15 '17 at 19:45
@michael that answer is about importing Python modules in the general case; the dunder init.py file is needed when the interpreter searches directories for modules to import, notebook or not. The above answer about the notebook interpreter working directory and setting PYTHONPATH is correct. – BoltzmannBrain Jul 15 '17 at 19:58
1

I did say there were going to be multiple correct answers, due to the wording of the question. I'm not implying this answer _isn't_ correct. But if using jupyter-notebook, you're just going to touch the file `__init_.py`, right? ...and, _not_ going to want to modify `PYTHONPATH` nor call `sys.path.append`, even if they are also correct (correct?). I mean, I have dozens of directories w/ code in them, and I'm not going to add them all to the path -- or expect other users to their jupyter config file, even if it's one directory. – michael Jul 15 '17 at 22:52
1

This was helpful for me. Especially because the __init__.py was in the correct folders and that had worked locally but not in jupyter... – Joseph Oct 28 '21 at 13:51

Mohideen bin Mohammed · Answer 2 · 2017-11-20T11:23:11.877

20

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

edited Nov 20 '17 at 11:23

answered Jan 14 '15 at 14:11

Mohideen bin Mohammed

18,813
10
112
118

1

By '__init.py__' you mean '\__init\__.py', right? I created the \__init\__.py as an empty file and it worked for me. Thanks a lot. But why is this needed? Before I had a python script in the same directory as my ipython notebook and the import was working fine. – Eduardo Reis Nov 18 '15 at 12:49
3

actually __init__.py is used to indicate python to indicate there is some package containing in that corresponding location. then only it will found sub modules whatever you created under it. if you doesn't create '_init_.py' means python don't know there is some package in it. Eg: from "Myfolder.Mypackage import Mymodules" for this eg, you should initiate __init__.py to indicate python to tell there is some package here. else it don't know. – Mohideen bin Mohammed Nov 19 '15 at 06:48
1

Yep, perfect answer. That's needed in python 2.7, but note in the 3 – Agape Gal'lo Nov 08 '16 at 14:03
this fixed the problem in python 3 for me. – Rick Apr 12 '17 at 04:33
fixed the problem for me, too -- using jupyter notebook, with python source in subdirectory of ipynb file; e.g., `foo.ipynb` using `bar/baz.py`, add empty `bar/__init__.py` file so that notebook can use `from bar.baz import MyClass` – michael Jul 15 '17 at 19:41
1

This hasn't solved it for me, and for so many others! – SarahJessica Nov 20 '20 at 12:14
Python 3.3 introduced that it is no longer necessary to inlcude `__init__.py` – pdaawr Aug 06 '21 at 11:27

z0r · Answer 3 · 2019-06-27T03:50:22.547

18

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.

edited Jun 27 '19 at 03:50

answered Jul 24 '15 at 01:08

z0r

8,185
4
64
83

having used miniconda to install a bunch of python related stuff I also got exactly this problem. The bundled ubuntu python 2.7 being different to the miniconda python 2.7. This answer allowed me to fix the issue – bph Feb 24 '16 at 21:51
4

This was my problem. I had upgraded to python 2.7.11 but my iPython interactive shell was still using 2.7.5. I just needed to run `pip install --upgrade ipython` to get the latest version and then it automatically used 2.7.11 by default. – Abundnce10 May 03 '16 at 17:46
My IPython is 7.4.0 while there's no such Python version at all. – aderchox Jun 27 '19 at 02:55
@aderchox Run this in ipython to get the interpreter version: `import sys; sys.version` – z0r Jun 27 '19 at 03:50

Jesse · Answer 4 · 2019-08-05T03:33:26.693

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

'ipython profile create' .... Yes! This is the only (permanent) solution that addresses jupyter notebook not reading from environment PATH and PYTHONPATH ... without resorting to messy sys.path statements at the start of every file (yuk). thank you @jesse. — JohnL_10, Mar 26 '20 at 22:29
@z0r 's solution confimed my issue, but #3 "Permanent Solution" here fixed it for me. — safay, Sep 14 '20 at 22:15

score 5 · Answer 5 · answered Jul 29 '14 at 18:37

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.

answered Jul 29 '14 at 18:37

acannon828

528
7
22

1

I'd have thought it better to set the PYTHONPATH on a per project basis instead of in every shell, e.g. with dotenv etc. – RobinGower May 25 '23 at 11:45

score 3 · Answer 6 · answered Jun 14 '17 at 22:07

3

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)

answered Jun 14 '17 at 22:07

pomber

23,132
10
81
94

score 3 · Answer 7 · edited May 22 '19 at 01:14

3

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.

edited May 22 '19 at 01:14

tshimkus

1,173
2
17
24

answered May 22 '19 at 00:02

Rui Guerra

31
1

score 2 · Answer 8 · answered Oct 01 '13 at 19:40

2

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.

answered Oct 01 '13 at 19:40

pandorabob

93
4

score 2 · Answer 9 · edited Sep 11 '17 at 10:22

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.

This will work if you always run the script from the same location. Otherwise, you'll run into problems since `os.getcwd()` gets the directory where the script was run, not the directory where the script file lives. — Nathan Arthur, Jun 24 '19 at 10:37

score 2 · Answer 10 · answered Sep 07 '19 at 18:52

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

score 1 · Answer 11 · answered May 01 '16 at 21:38

1

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

answered May 01 '16 at 21:38

peter n

1,210
13
18

score 1 · Answer 12 · answered Mar 02 '22 at 11:03

This problem occurs due to the different versioning - e.g. 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.

score 1 · Answer 13 · answered Mar 15 '23 at 03:42

One very subtle way this could happen is when your filename is the same as the anaconda environment name. This happened to me as the exact same code in two different files where one was accidentally named as the anaconda environment threw the "no module found error".

score 0 · Answer 14 · answered Jul 12 '17 at 09:59

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...)

score 0 · Answer 15 · answered Mar 02 '19 at 23:24

Solution without scripting:

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

score 0 · Answer 16 · answered Apr 10 '19 at 06:35

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

Run command $ pip --version and $ pip3 --version to check which pip is from at Python 3x. E.g. 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

score 0 · Answer 17 · answered Sep 03 '19 at 19:55

0

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.

answered Sep 03 '19 at 19:55

subtleseeker

4,415
5
29
41

score 0 · Answer 18 · answered Feb 12 '20 at 19:33

0

This answer applies to this question if

You don't want to change your code
You don't want to change PYTHONPATH permanently

Temporarily modify PYTHONPATH

path below can be relative

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

answered Feb 12 '20 at 19:33

kon psych

626
1
11
26

score 0 · Answer 19 · edited Aug 04 '21 at 19:46

0

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

edited Aug 04 '21 at 19:46

Haifeng Zhang

30,077
19
81
125

answered Mar 04 '20 at 16:39

shiva kumar

11,294
4
23
28

score 0 · Answer 20 · answered Aug 21 '21 at 21:29

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!

score 0 · Answer 21 · answered May 09 '22 at 08:57

0

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()

answered May 09 '22 at 08:57

Jens

201
4
6

score 0 · Answer 22 · answered Jul 04 '22 at 08:50

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.

score -1 · Answer 23 · edited Oct 29 '19 at 19:44

-1

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

pip install pathlib

edited Oct 29 '19 at 19:44

double-beep

5,031
17
33
41

answered Jun 05 '17 at 05:22

user3233042

39
1
2

"ImportError: No module named" when trying to run Python script

23 Answers23

Linked