Python functions to compress folder paths to include their environment variable. This is the opposite of os.path.expandvars(). For example, "C:\Windows\system32\cmd.exe" would resolve to "%WINDIR%\system32\cmd.exe".

gistfile1.py

#@bbaskin
import os
import re

# Thanks to Andrew Havens of Cipher Tech for figuring out how to escape the paranthesis to work with
# both expandvars and regex

def generalize_vars_init():
    """
    Initialize a dictionary with the local system's environment variables.

    Returns:
      path_generalize_list: A Python dictionary of path:variable.
    """
    
    envvar_list = [r'%ALLUSERSPROFILE%',
                   r'%LOCALAPPDATA%',
                   r'%APPDATA%',
                   r'%COMMONPROGRAMFILES%',
                   r'%PROGRAMDATA%',
                   r'%PROGRAMFILES%',
                   r'%PROGRAMFILES(x86)%',
                   r'%PUBLIC%',
                   r'%TEMP%',
                   r'%USERPROFILE%',
                   r'%WINDIR%']

    path_generalize_list = {}
    for env in envvar_list:
        resolved = os.path.expandvars(env).encode('unicode_escape')
        resolved = resolved.replace('(', '\\(').replace(')', '\\)')
        if not resolved == env:
            path_generalize_list[resolved] = env
    return path_generalize_list


def generalize_var(d, string):
    """
    Performs a multiple find/replace on a string based on a given dictionary.

    Args:
      d: Python dictionary of text as: search:replace
      string: string to perform replacement on
    Returns:
      A string value with replacements made.
    """    
    
    search = '(?i)' + '|'.join('(%s)' % key for key in d.iterkeys())
    regex = re.compile(search)
    lookup = dict((index + 1, value) for index, value in enumerate(d.itervalues()))
    return regex.sub(lambda match: match.expand(lookup[match.lastindex]), string)


if __name__ == '__main__':
    lookup = generalize_vars_init()
    strings = [r'C:\Windows\System32\cmd.exe', r'C:\Program Files\testing123', r'C:\ProgramData\Folder\File']
    for s in strings:
        print ('%s => %s' % (s, generalize_var(lookup, s)))