How to change the python version that a virtual environment uses in Ubuntu 14.04? [duplicate]

Answer 1

Activate your old Python 2.7 enviroment:

source /path/to/your/env/bin/activate

Save dependencies:

pip freeze > env.txt

Create new Python 3.x enviroment:

virtualenv -p python3 newenvname

Activate new environment and install all dependencies from the old environment from env.txt:

source newenv/bin/activate
pip install -r env.txt