How to evaluate environment variables into a string in Python?
Use os.path.expandvars to expand the environment variables in the string, for example:
>>> os.path.expandvars('$C/test/testing')
'/stackoverflow/test/testing'
In Python 3 you can do:
'{VAR}'.format(**os.environ))
for example
>>> 'hello from {PWD}'.format(**os.environ))
hello from /Users/william