python virtualenv does not use correct version of python

Question

I'm creating a Django app that requires me to use python2.7.6 . My system has python3.4.1 installed so I have to use a virtualenv with python2.7 installed. I installed such a virtualenv using Pycharm and named it django_python_2.7 but when I activate it in the terminal and run "python", it still shows that it's using system's python3.4.1: here is what I did:

1. Activate the environment:

   source django_python_2.7/bin/activate

2. Run python, and it shows:

   Python 3.4.1 (v3.4.1:c0e311e010fc, May 18 2014, 00:54:21) ---> this is the system level python and not the one installed in virtualenv

However, when I run which python, it shows the correct path that points to virtualenv's python version:

/Users/calvinmwhu/....../django_python_2.7/bin/python

When I explicitly run the python version installed in that virtualenv:

django_python_2.7/bin/python

it shows the correct version:

Python 2.7.6 (default, Sep  9 2014, 15:04:36) 

I have no idea what's going on. I'm developing this app in Pycharm IDE but I really like executing commands in the terminal . But in the terminal the virtualenv is not using the correct version of python..Why does running a simple "python" command in the virtualenv still default to the system's python ?

Could anyone provide some hints? Is it necessary to change the PATH variable to make it contain the path to the virtualenv's python?

Answer 1

If you want to change the PYTHONPATH used in a virtualenv, you can add the following line to your virtualenv's django_python_2.7/bin/activate file

export PYTHONPATH="/path/to/python"
export OLD_PYTHONPATH="$PYTHONPATH"

To restore to its original value on deactivate, you could add following line to your django_python_2.7/bin/postdeactivate script.

export PYTHONPATH="$OLD_PYTHONPATH"

Otherwise, create new env using

virtualenv -p /usr/bin/python2.7 django_python_2.7