Creating an isolated Python runtime environment with VIRTUALENV

In the Ubuntu 14.04 system, for example, the Python and Python3 installed are 2.7.6 and 3.4.3, but some projects require a specific Python version. The current system default Python is already closely coupled with the system, you can not arbitrarily uninstall or upgrade the default Python, otherwise it may cause the system is not available. In this case, you can use Virtualenv to create a Python isolated environment that resolves multiple versions of conflicts between different applications. The specific installation and use steps are as follows,

Install Virtualenv,

sudo Install virtualenv

Create a clean Python runtime environment, named PvE, the parameter--no-site-package means not to copy the installed third-party package to the newly created Python environment, run completion will generate folder PvE in the current directory,

$ virtualenv--no-site-packages PvE

As the next command enters the new Python virtual environment, in the virtual environment, you can install a variety of required third-party packages, without affecting the host's Python environment,

$ source Pve/bin/activate

To exit the Python virtual environment, the command is as follows,

Finish.

Creating an isolated Python runtime environment with VIRTUALENV