Working with environment variables

Environment variables are part of operating systems and affect system operations. Python has Python-specific variables that affect how Python functions, that is, the behavior of the Python interpreter. While they are processed before command-line options, the command-line switches will override environment variables if there is a conflict.

How to do it...

1. Environment variables are accessed via Python's os.environ.
2. Because the environ object is a dictionary, you can specify a particular variable to view:

      >>> import os
      >>> print(os.environ["PATH"])
      /home/cody/anaconda3/bin:/home/cody/bin:/home/cody/
      .local/bin:/usr/local/sbin:/usr/local/bin:/usr
       /sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games

3. Adding a new variable is as simple as follows:

      >>> os.environ["PYTHONOPTIMIZE"] = "1"

How it works...

There are a large number of Python-specific environment variables available. Some of them are:

• PYTHONHOME...