Incorrect PythonPath after editting bash_profile for Mac trying to install OpenCV

Question

Total noob here trying to get OpenCV working on Python through Homebrew. I searched everywhere extensively and couldn't find an answer intelligible to me. 99% of what I have done for this install is blindly follow forum posts, though I am beginning to get an understanding of what all this means.
Installed software:

OS 10.7.4
Xcode 4.4.1
-Command Line Tools
HomeBrew
-Python
-GFortran
-OpenCV

1. write this on first line of .bash_profile and save and restart Mac
export PYTHONPATH="/usr/local/lib/python2.7/site-packages:$PYTHONPATH"

2. open IDLE located at /usr/local/Cellar/python/2.7.3
.>>> import cv

Traceback (most recent call last):
File "", line 1, in
import cv
File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/cv.py", line 1, in
ImportError: No module named cv2.cv

3. Go to Terminal to check PATH and PYTHONPATH
myname-MacBook-Pro:~ myname$ set
.#edited out unnecessary lines PATH=/opt/local/bin:/opt/local/sbin:/opt/local/bin:/opt/local/sbin:/opt/local/bin:/opt/local/sbin:/opt/local/bin:/opt/local/sbin:/opt/local/bin:/opt/local/sbin:/opt/local/bin:/opt/local/sbin:/Library/Frameworks/Python.framework/Versions/2.7/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin PYTHONPATH=/usr/local/lib/python2.7/site-packages:

1) What does my PATH need to be? I know its comically out of whack from repeated attempts.
2) Why isnt IDLE using this PYTHONPATH?
3. And most importantly, WHAT DO I NEED TO DO OVERALL TO JUST GET AN ICON, ON MY DOCK, THAT I CAN CLICK, THAT OPENS A PROGRAM, WHERE I CAN CODE WONDERFUL PYTHON WITH MAGNIFICENT OPENCV.

Thank you very much for any help you can send my way. I have been attempting to solve this problem for the last 3 days and would be very very appreciative of any help.

Your PYTHONPATH here is correct. Notice that the file path in the traceback when you try to import cv is pointing to the correct location. The problem is that cv then tries to import from cv2, which doesn't seem to exist. How did you install OpenCV? Is there a cv2 file or package in your python2.7/site-packages? — Matthew Trevor

katharos katharos · Accepted Answer · 2014-09-12T21:24:38

So IDLE is a regluar application not a commandline program that you run from bash, so it's not going to read your .bash_profile or your environment variables like PYTHONPATH.

The good news is, there is a way to get IDLE to recognise new python modules which might be in unusual locations, they just need to be referenced from a place where IDLE expects them to be, which is the site-packages directory. The confusing part is that you probably have more than one version of Python installed since Python is installed by default in Mac OSX and you've also installed it with homebrew (and it looks like you've tried macports as well).

Based on the path in the error, we know that IDLE is looking for the module in /usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/ which is the homebrew installation.

It looks like you somehow have the cv module there or linked in the site-packages directory but you're missing some other necessary file(s).

I have not installed OpenCV myself, but from the instructions here: http://jjyap.wordpress.com/2014/05/24/installing-opencv-2-4-9-on-mac-osx-with-python-support/ It looks like you need to also symlink the opencv cv2.so file into your site-packages directory from the opencv files you got through homebrew. (note the path for your site-packages directory is different from the instructions in the link).

Incorrect PythonPath after editting bash_profile for Mac trying to install OpenCV

1 Answers