how to make environmental variable appear in os.environ code example

Example 1: get all environment variables python

""" lists environment variables, and splits elements in path variable """
import os


for k, v in sorted(os.environ.items()):
    print(k+':', v)
print('\n')
# list elements in path environment variable
[print(item) for item in os.environ['PATH'].split(';')]

Example 2: get environment variable python

import os

# Set environment variables
os.environ['API_USER'] = 'username'
os.environ['API_PASSWORD'] = 'secret'

# Get environment variables
USER = os.getenv('API_USER')
PASSWORD = os.environ.get('API_PASSWORD')

# Getting non-existent keys
FOO = os.getenv('FOO') # None
BAR = os.environ.get('BAR') # None
BAZ = os.environ['BAZ'] # KeyError: key does not exist.