Question or problem about Python programming:
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.
How to solve the problem:
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
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.
Just create an empty python file with the name
__init__.py under the folder which showing error, while you running the python project.
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]
sys.path was different between the two interpreters. To fix it, I removed Python 3.3.
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
import sys sys.path.append('/home/osboxes/miniconda2/lib/python2.7/site-packages') import cv2
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")' ]
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