Python

Python is a widely used general-purpose, high-level programming language.

Python Versions

Most modern *NIX systems ship with a default version of Python. If the default version is not sufficient, there are multiple version of Python are available via GNU Modules. If you find that you need a version of Python that is not currently available through GNU Modules, you can always build it from source.

Python Environment

Python utilizes a variable called 'PYTHONPATH', which is similar to the PATH variable used in many shells. The PYTHONPATH variable tells they Python interpreter where to look to find modules. To View your python path:

bash:~$ python -c 'import sys; print sys.path'

You can add directories to your PYTHONPATH either through your shell, or in your Python code itself:

bash:~$ PYTHONPATH=$PYTHONPATH:/location/to/directory

                 ...or...

>>> sys.path.append('/location/to/directory')

Installing Modules

While some of the Versions of Python available in GNU modules provide a default set of modules pre-installed, you may wish to install your own. Typically you will not have access to the global Python install location, so you will have to install modules using an alternative method.

Unix/Linux Alternate Module Installation

'User' scheme

The user scheme allows a suer to install the module into the site userbase (python -c 'import site; print site.USER_BASE'). This file location is included in the PYTHONPATH by default.

bash:~$ python setup.py install --user

'Prefix' scheme

The prefix scheme allows a user to install a module into a location of their choice. Please note: This location will need to be added to the PYTHONPATH in order for the module to be found by python.

bash:~$ python setup.py install --prefix="/path/to/location"

Python Virtual Environment

A Python Virtual Environment is an isolated working copy of Python which allows you to work on a specific project without worry of affecting other projects. For more information on setting up a virtualenv, please see the Python Virtual Environment page.

Windows Alternate Module Installation:

Prefix Scheme

Python on windows has a simpler layout, and as such the prefix scheme has traditionally been used to install additional packages intoa separate location.

python setup.py install --prefix="\Temp\Python"