Question

I’ve been using python 2.7 and after installation of python 2.7. All of the scripts have run successfully, but suddenly today, when I run python, it is recognized with python 2.6, so for one of the python packages I get the following error:

/Library/Frameworks/Python.framework/Versions/2.6/Resources/Python.app/Contents/MacOS/Python: 
No module named htseq-count

i am not sure why it happens. The path environment variable for python is set to:

PATH="/Library/Frameworks/Python.framework/Versions/2.7/Resources/bin:${PATH}" export PATH

How do I fix this error?

Answer 1

If your code relies on a particular version of Python, you should specify python2.7 or python2.6 instead of just python.

If this “suddenly” happened it’s possible that installing some other software modified your $PATH so that the old version of Python now has priority (it’s possible for multiple versions to be on your $PATH; it uses the first one it finds).

If you move these two lines to the bottom of the file they’re in (maybe ~/.profile) it may correct this.

PATH="/Library/Frameworks/Python.framework/Versions/2.7/Resources/bin:${PATH}"
export PATH

You can type which python in Terminal you can see what binary it finds when looking for python on your $PATH.

If you don’t mind using Python 2.6, you can probably install the missing package by typing this in your terminal:

easy_install-2.6 htseq