Refresh imported value from a python module

Question

I have a project with project with several files for one I declare one variable as None and then inside a function I update it's value.

module_1.py

import pandas as pd
df_data = None
def read_files():
    global df_data
    df_data=pd.read_xlsx('dummy.xlsx')

module_2.py

from module_1 import df_data
from module_1 import read_files

read_files()
print(df_data)
# This returns None

I thought that being a global variable it would update even after importing because from module_1.py file I'm updating its value. But its none.

I think its because python imports the module initially with the value None, and even if set as global it won't reload the value.

I could do a get function, but is there any other way?

What's the correct way to do this? Make a get function and return the object itself? Is there any way to refresh variables after importing them?

Answer 1

TLDR: change the from import in module_2

import module_1
from module_1 import read_files

read_files()
print(module_1.df_data)

Explanation: your from module_1 import df_data creates a reference in the scope of module_2 to df_data from module_1. In your read_files() function you replace the value of df_data in the global scope of module_1, but this (as you figured it out) doesn't change anything in the scope of module_2.