Python modules not being detected although they are installed

Question

I had an old version for Python. Then I uninstalled the old version, and install a new one - 2.7.9.

I set the 2.7.9 as my global version via pyenv but all my modules not being detected. They were installed before the upgrading. Now I uninstalled them and reinstall but still not working...

~/Projects/development$ python
Python 2.7.9 (default, Mar  3 2016, 16:42:45) 
[GCC 4.6.3] on linux2
>>> from github import Github
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named github

They already reinstalled after the python upgrading! Trying to install them again, gives Requirement already satisfied error.

~/Projects/development$ pip install PyGithub
Requirement already satisfied (use --upgrade to upgrade): PyGithub in /usr/local/lib/python2.7/dist-packages
Cleaning up...

What can I do?

~/Projects/development$ pyenv versions
  system
* 2.7.9 (set by /home/user/.pyenv/version)

~/Projects/development$ python
    Python 2.7.9 (default, Mar  3 2016, 16:42:45) 
    [GCC 4.6.3] on linux2
>>> sys.executable
'/usr/local/bin/python'
>>> sys.exec_prefix
'/usr/local'
>>> print '\n'.join(sys.path)

/usr/local/lib/python27.zip
/usr/local/lib/python2.7
/usr/local/lib/python2.7/plat-linux2
/usr/local/lib/python2.7/lib-tk
/usr/local/lib/python2.7/lib-old
/usr/local/lib/python2.7/lib-dynload
/usr/local/lib/python2.7/site-packages

which pip gives /usr/bin/pip.

Answer 1

I found the problem.

dist-packages vs. site-packages.

Using prev Python version, and also after upgrading, my packges were installed by pip to /usr/local/lib/python2.7/dist-packages, whereas the new Python I installed expects packages to be installed to /usr/local/lib/python2.7/site-packages (When manually installing Python from source, it uses the site-packages directory. See more here). I can temporary copy the modules, or just manipulate the PYTHONPATH environment variable to point to dist-packages in order to gain access to the installed packaged with the newly installed version of Python.

From here.