os.environ

Syntax: os.environ

Parameter: It is a non-callable object. Hence, no parameter is required

Return Type: This returns a dictionary representing the user’s environmental variables

os.environ in Python is a mapping object that represents the user’s environmental variables. It returns a dictionary having user’s environmental variable as key and their values as value.

# Python program to explain os.environ object 

# importing os module 
import os 
import pprint 

# Get the list of user's 
# environment variables 
env_var = os.environ 

# Print the list of user's 
# environment variables 
print("User's Environment variable:") 
pprint.pprint(dict(env_var), width = 1) 

os.environ behaves like a python dictionary, so all the common dictionary operations like get and set can be performed. We can also modify os.environ but any changes will be effective only for the current process where it was assigned and it will not change the value permanently.

# Python program to explain os.environ object 


# importing os module 
import os 

# Method 1 
# Print the value of 
# 'MY_HOME' environment variable 
print("MY_HOME:", os.environ.get('MY_HOME', "Environment variable does not exist")) 


# Method 2 
try: 
    print("MY_HOME:", os.environ['MY_HOME']) 
except KeyError: 
    print("Environment variable does not exist")