Env Variables in Python (v3.0) on Windows

Hello all. I'm using Python 3.0.

How to expand an environment variable given the %var_name% syntax?

Any help is much appreciated! Thanks!

From stackoverflow

• I'm guessing you mean "How do I get environment variables?":

  import os
  username = os.environ['UserName']
  

  Alternatively, you can use:

  username = os.getenv('UserName')
  

  And to add/change your own variables, you can use:

  os.putenv('MyVar', 'something I want to store')
  

• It's in a slightly unexpected place: os.path.expandvars(). Admittedly it is quite often used for processing paths:

  >>> import os.path
  >>> os.path.expandvars('%APPDATA%\\MyApp')
  'C:\\Documents and Settings\\Administrator\\Application Data\\MyApp'
  

  but it's a shell function really.