Saving output after choosing option menu (python - Tkinter)

Question

I'm attempting to save the choice of the user [Red, Green-red, Green-blue, blue] after the user hits the okay button and the window closes in Tkinter... I've put this together so far using things I've found online but I can't deduce a "simple" way of doing this?

def select_channel():
     OPTIONS = [
       "Red",
       "Green-red",
       "Green-blue",
       "Blue"
    ]

    master = tk.Tk()

    var = tk.StringVar(master)
    var.set(OPTIONS)  # initial value

    option = tk.OptionMenu(master, var, *OPTIONS)
    option.pack()


    def ok():
       print("value is", var.get())
       channel = var.get()
       master.destroy()

    button = tk.Button(master, text="OK", command=ok)
    button.pack()
    tk.mainloop()

Any thoughts? I save it under channel but its not available outside of that function. hmm

Answer 1

Use global to assign value to global variable

def ok():
    global channel

    print("value is", var.get())
    channel = var.get()
    master.destroy()

---

BTW: There is no sense to use return channel because function is executed by button and it can't returned value and assign to other value.

---

BTW: If you want save only channel then maybe do it inside function ok()

---

BTW: You should use [0] in var.set(OPTIONS[0]) to set only first element as default/initial value.

---

import tkinter as tk

# --- functions ---

def select_channel():

     def ok():
         global channel

         #print("value is", var.get())
         channel = var.get()
         master.destroy()

     OPTIONS = [
       "Red",
       "Green-red",
       "Green-blue",
       "Blue"
     ]

     master = tk.Tk()

     var = tk.StringVar(master)
     var.set(OPTIONS[0])  # initial value

     option = tk.OptionMenu(master, var, *OPTIONS)
     option.pack()

     button = tk.Button(master, text="OK", command=ok)
     button.pack()

     tk.mainloop()

# --- main ---

select_channel()
print('after closing window:', channel)