Professional IronPython

ACCEssIng THE sTAndARd LIbRARy FRoM IRonPyTHon
Before you can use the Python Standard Library to create applications, you must provide a means 
for IronPython to find the Standard Library so it can import modules. You have three options for 
performing this task.
➤➤
Create an environment variable named 
IRONPYTHONPATH
and provide the path to the 
Standard Library through it. The “Understanding the IPY.EXE Command Line Syntax” 
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Accessing the Standard Library from IronPython
 
❘
 
103
section of Chapter 1 tells you how to work with environment variables. This option is 
machine-specific, but it does work.
➤
➤
Manually add the path to the import search path (discussed later in this section). The advan-
tage of this method is that the import requirements move with the application. However, if the 
user has their copy of the Standard Library in a different location (or doesn’t have the Standard 
Library installed at all), the change can break your application.
➤
➤
Add the path to 
site.py
, which is located in the 
\Program Files\IronPython 2.6\Lib
directory of your machine. The interpreter loads this file every time it starts, so you can be 
sure that everyone using the IronPython interpreter on your machine will have the required 
access. As with the 
IRONPYTHONPATH
environment variable, this solution works on the cur-
rent machine only.
Manually Adding the Import search Path
In order to manually add the import search path, you need to add code to every application created. 
The code isn’t long or hard to understand, but you must add it to every application that requires the 
Standard Library or the application won’t be able to access it. Here’s an example of the code you need.
import sys
sys.path.append(‘C:\Python26\Lib’)
In this case, my copy of the Standard Library is located in 
C:\Python26\Lib
, which is the default 
setup. You need to change this value to match your system. After you make the change, you can 
verify that it’s correct by using the following code.
print sys.path[len(sys.path)-1]
All that this code does is display the last path added to 
sys.path
. If you see the appropriate path, 
you know you’re ready to go.