I have a string containing an environment variable, e.g.
my_path = '$HOME/dir/dir2'
I want parse the string, looking up the variable and replacing it in the string:
print "HOME =",os.environ['HOME']
my_expanded_path = parse_string(my_path)
print "PATH =", my_expanded_path
So I should see the output:
HOME = /home/user1
PATH = /home/user1/dir/dir2
Is there an elegant way to do that in Python?
Use : os.path.expandvars
os.path, considering environment variables are used for more than file-system path elements. I guess I could use os.path.expandvars('%username%') instead of getpass.getuser().
os.path.expandvars will not expand and leave intact expressions using variables that are not set.
os.path because it's main purpose is to expand environment variables that point to directories. For all other purposes you should use os.environ instead.import string, os
my_path = '$HOME/dir/dir2'
print string.Template(my_path).substitute(os.environ)
You could use a Template:
from string import Template
import os
t = Template("$HOME/dir/dir2")
result = t.substitute(os.environ)
