Environment variables, as the name suggests, are
variables in your system that can affect the way running processes will behave on a computer. It is actually a combination of values, called
key/pair values . The most well known
environment variable is probably PATH which contains the paths to all folders that might contain executables. The concept of environment variables exists in most
operating systems , from Linux to OS X to Windows.
In Python, environment variables are accessed through
os.environ .
import os
print(os.environ['PATH'])
How to set and get environment variables in Python?
In order to
set and get environment variables in Python you can just use the following code:
import os
# Set environment variables
os.environ['API_USER'] = 'newuser'
os.environ['API_PASSWORD'] = 'mypass'
# Get environment variables
USERNAME = os.getenv('API_USER')
PASSWORD = os.environ.get('API_PASSWORD')
Dictionary Operations
Python
os.environ behaves like a python dictionary, so all the common
dictionary operations can be performed.
If you want to see a list of all the
environment variables use the following code:
>>> print(os.environ)
The following program will print all of the environment variables
along with their values .
import os
for key, value in os.environ.items():
print('{}: {}'.format(key, value))
How to check environment variables exists in Python?
import os
import sys
try:
os.environ["MYVAR"]
except KeyError:
print("Please set the environment variable MYVAR")
sys.exit(1)
Or
import os
if ('PATH' in os.environ):
print("Key exist")
else:
print("Key does not exist")