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Python | os.getenv () method

os.getenv() in Python returns the value of the environment variable key if it exists, otherwise it returns the default.

Syntax: os.getenv (key, default = None)

Parameters:
key: string denoting the name of environment variable
default (optional): string denoting the default value in case key does not exists. If omitted default is set to `None`.

Return Type: This method returns a string that denotes the value of the environment variable key. In case key does not exists it returns the value of default parameter.

Code # 1: using the os.getenv () method

# Python program to explain the os.getenv () method

 
# import of the os module

import os

 
# Get the value & # 39; HOME & # 39;
# environment variable

key = `HOME`

value = os.getenv (key)

 
# You enter the value & # 39; HOME & # 39;
# environment variable

print ( "Value of` HOME` environment variable: " , value) 

 
# Get the value & # 39; JAVA_HOME & # 39;
# environment variable

key = `JAVA_HOME`

value = os.getenv (key)

 
# Print the value & # 39; JAVA_HOME & # 39;
# environment variable

print ( "Value of` JAVA_HOME` environment variable: " , value) 

Output:

 Value of `HOME` environment variable: / home / ihritik Value of` JAVA_HOME` environment variable: /opt/jdk-10.0.1 

Code # 2: if the key does not exist

# Python program to explain the os.getenv () method

 
# import of the os module

import os

  
# Get home value
# environment variable

key = `home`

value = < code class = "plain"> os.getenv (key)

 
# Print the value & # 39; home & # 39;
# environment variable

print ( "Value of` home` environment variable: " , value)

Exit:

 Value of `home `environment variable: None 

Code # 3: explicitly specifying the default

# Python program to explain the os.getenv () method

 
# module import os

import os

  
# Get home value
# environment variable

key = `home`

value = os.getenv (key, "value does not exist" )

 
# Print the value & # 39; home & # 39;
# environment variable

print ( "Value of` home` environment variable: " , value) 

Exit:

 Value of `home` environment variable: value does not exist 
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