Importing class variable form another file Python

Question

I am trying to import a specific class variable from another file in Python 3. However, I am not sure how to do this corretly or even make it to work at all.

File "gui.py"

class Gui:
    def __init__(self):
        self.board = [0]

    def run(self):
        self.board = [2]

if __name__ == '__main__':
    Gui().run()

In file eval.py below I want to use the updated variable self.board = [2] from gui.py. I tried below code examples but got the error "AttributeError: type object 'Gui' has no attribute 'board'" in both cases.

File "eval.py"

from gui import Gui

board = Gui.board

board = __import__('gui').Gui.board

I also tried to remove the name=main thing from gui.py but as expected it only made gui.py run its code and then I got the same error as previously.

How do I access the variable self.board from Gui.run() from gui.py in eval.py in the best and most efficient possible way?

Answer 1

Try this:

test.py

class Gui:
    def __init__(self):
        self.board = [0]

    def run(self):
        self.board = [2]        

test1.py

from test import Gui

boardObj = Gui()
boardObj.run()

print(boardObj.board)

Run test.py and you will be able to access board from test1.py file and it will be modified to [2].

Example of class variable:

test.py

class Gui:
    board = [5]
    def __init__(self):
        self.board = [0]
    def run(self):
        self.board = [2]   

test1.py

from test import Gui

print(Gui.board)

obj = Gui()
obj.run()

print(obj.board)

Gui.board(class variable) will give you ans [5] and obj.board(instance variable) will give you ans [2]

Answer 2

This has nothing to do with importing.

board is an instance variable, not a class one. You need an instance of Gui:

gui = Gui()
gui.run()
print(gui.board)