Sunday 1 January 2017

python - How to access environment variable values?



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


Answer



Environment variables are accessed through os.environ



import os

print(os.environ['HOME'])


Or you can see a list of all the environment variables using:



os.environ


As sometimes you might need to see a complete list!




# using get will return `None` if a key is not present rather than raise a `KeyError`
print(os.environ.get('KEY_THAT_MIGHT_EXIST'))

# os.getenv is equivalent, and can also give a default value instead of `None`
print(os.getenv('KEY_THAT_MIGHT_EXIST', default_value))


Python default installation on Windows is C:\Python. If you want to find out while running python you can do:



import sys

print(sys.prefix)

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