How to set environment variables in Python
I need to set some environment variables in the python script and I want all the other scripts that are called from python (shell scripts) which will be child process to see the environment variables set. The value is a number.
If I do os.environ["DEBUSSY"] = 1 , it complains saying that 1 has to be string. I also want to know how to read the environment variables in python (in the later part of the script) once I set it.
Environment variables must be strings, so use
os.environ["DEBUSSY"] = "1"
to set the variable DEBUSSY to the string 1 . To access this variable later, simply use
print os.environ["DEBUSSY"]
Child processes automatically inherit the environment of the parent process -- no special action on your part is required.
You may need to consider some further aspects for code robustness;
when you're storing an integer-valued variable as an environment variable, try
os.environ['DEBUSSY'] = str(myintvariable)
then for retrieval, consider that to avoid errors, you should try
os.environ.get('DEBUSSY', 'Not Set')
possibly substitute '-1' for 'Not Set'
so, to put that all together
myintvariable = 1
os.environ['DEBUSSY'] = str(myintvariable)
strauss = int(os.environ.get('STRAUSS', '-1'))
# NB KeyError <=> strauss = os.environ['STRAUSS']
debussy = int(os.environ.get('DEBUSSY', '-1'))
print "%s %u, %s %u" % ('Strauss', strauss, 'Debussy', debussy)
if i do os.environ["DEBUSSY"] = 1, it complains saying that 1 has to be string.
Then do
os.environ["DEBUSSY"] = "1"
I also want to know how to read the environment variables in python(in the later part of the script) once i set it.
Just use os.environ["DEBUSSY"] , as in
some_value = os.environ["DEBUSSY"]
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