Python os.getenv() Method

The os.getenv() method is a built-in function in the OS module. It is used to obtain the value of an environment variable.

Syntax of os.getenv():

os.getenv(key, default=None)

Parameters

Return

The os.getenv() method returns the value of the environment variable.

Example Codes: Use the os.getenv() Method to Get the Environment Variable Value

In the following example, we will get the value of the data environment variable.

import os

data = "VARIABLE"
path = os.getenv(data)
print(path)

Output:

This will return the value of the VARIABLE environment variable.

Example Codes: Use the os.getenv() Method With the Default Parameter

In the following example, we will get the value of the USERNAME environment variable. The default value (Guest) will be returned if the environment variable is not found.

import os

username = os.getenv("DATA", "Guest")
print(username)

Output:

Guest

Example Codes: Possible Error While Using the os.getenv() Method

If the key is not a string, then a TypeError will be raised. In the following example, we will try to get the value of an environment variable with an integer key.

import os

os.getenv(1)

Output:

TypeError: the key must be a string