python module paths that I set have gone when I restart python

Question

I was trying to add another module path. Let's say I want to append path 'd'

$ python3
>>> import sys
>>> sys.path
['a','b','c']

>>> sys.path.append('d')
>>> sys.path
['a','b','c','d']

>>> exit()
$python3
>>> import sys
>>> sys.path
['a','b','c']

The path I added is gone when I restart python. I would like to set the path 'd' as default.

Answer 1

The program restarts and sets to original settings, with only assigned values, that are in the program, when you open python again. I'd say you're best bet would be to add the

sys.path.append('d')
sys.path

lines of code into the main code.

There is another way, but it isn't 100% accurate and reliable. If you saved this program(you have to save the program) as, lets say, script.py, all you have to do is at the beginning of a new file type,

from script import *

(It helps if the file name isn't an actual module). This way may not work, and it has to have both files in the same folder, but it's the best way I know.