How to access environment variable values?

Question

I set an environment variable that I want to access in my Python application. How do I get its value?

Answer 1

To check if the key exists (returns True or False)

'HOME' in os.environ

You can also use get() when printing the key; useful if you want to use a default.

print(os.environ.get('HOME', '/home/username/'))

where /home/username/ is the default