Development programming, environmental variables

Ok im writing a python script which reads from a file in a specific location, does anyone know if theres a way to use the windows environmental variables to give the path to the file, for example the %SYSTEMDRIVE% variable incase people dont have C:\ as their mine drive.

Thanx

 

GIYF

From Red Hat® Linux 6 Unleashed Chapter 34: Programming in Python

(but AFAIK it's the same deal under Windows.)

Environment variables are accessed in Python through the os module's environ dictionary. Because it's a dictionary, lookups are done with the os.enEviron[VARNAM] syntax, with the environment variable's name in quotes. That syntax throws a KeyError exception if VARNAME isn't in the environment. Unfortunately, an missed KeyError exception will clumsily terminate the program. To prevent that, the try, except, else syntax is used to handle any KeyError exception. Note the following code:

Code:

#!/usr/bin/python 
import os

def printenv(s):
   try:
      x = os.environ[s]
   except KeyError:
      print "No such environment var:", s
   else:
      print "Env var", s, "has value:", x

printenv("SHELL")
printenv("OSTYPE")

Cheers

Graeme