Installing Python modules

The following was taken from the online tutorial: http://www.tutorialspoint.com/python/python_modules.htm

When you import a module, the Python interpreter searches for the module in the following sequences −

(1) The current directory.

If the module isn't found, Python then searches each directory in the shell variable PYTHONPATH.

If all else fails, Python checks the default path. On UNIX, this default path is normally /usr/local/lib/python/.

The module search path is stored in the system module sys as the sys.path variable. The sys.path variable contains the current directory, PYTHONPATH, and the installation-dependent default.

The PYTHONPATH Variable:

The PYTHONPATH is an environment variable, consisting of a list of directories. The syntax of PYTHONPATH is the same as that of the shell variable PATH.

Here is a typical PYTHONPATH from a Windows system:

set PYTHONPATH=c:\python20\lib;

And here is a typical PYTHONPATH from a UNIX system:

set PYTHONPATH=/usr/local/lib/python