In Python script, how do I set PYTHONPATH?

Question

I know how to set it in my /etc/profile and in my environment variables.

But what if I want to set it during a script? Is it import os, sys? How do I do it?

Answer 1

You can get and set environment variables via os.environ:

import os
user_home = os.environ["HOME"]

os.environ["PYTHONPATH"] = "..."

But since your interpreter is already running, this will have no effect. You're better off using

import sys
sys.path.append("...")

which is the array that your PYTHONPATH will be transformed into on interpreter startup.