[Tkinter] HOW TO: Use Globals In Module ???

[Webtest]

Esteemed Forum Participants and Lurkers:
Platform: Linux Mint 18.3 Mate 64-bit, Python 3.5.2 & Idle3
I am working on a Python 3 program using TKinter which is essentially a keystroke driven state machine. I want to segregate the different states in 'modules'. The 'root' TKinter window is global to the whole program, but I can't seem to make it visible to a module, EXCEPT I CAN pass it to a function in a module as a parameter.
How do I make it available to the function as a global object which is what I REALLY want to learn how to do?

Main Program:

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# Module Test for Globals and Modules import tkinter as tk   Groot = tk.Tk()  # Create the GLOBAL root window Glabel1 = []     # Global Label identifier GCOUNT = 0       # Global Keystroke counter   # Pull in the "setup" module import setup # Create and load the display label setup.setup()   # #########  Keyboard 'Keypress' event handler  ######### def key(event):     global GCOUNT     GCOUNT += 1     msg = '%d %r %d %d' %(GCOUNT,event.keysym,event.keysym_num,event.state)     print(msg) # #######################################################   # Bind the Keypress event to the 'key' event handler Groot.bind_all('<Key>', key) # Exit to the running event-driven app Groot.mainloop()

Test Module:

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# MODULE "setup.py" in moduletest import tkinter as tk   # GLOBALS: global Groot global Glabel1   def setup():     # Create and load the display label into the window     prompt = '        Press any key        '     Glabel1 = tk.Label(Groot, text=prompt, width=len(prompt), bg='yellow')     Glabel1.pack()     return()

Here is the error message:
Traceback (most recent call last):
File "/media/mint/python/keystroke.py", line 19, in <module>
setup.setup()
File "/media/mint/python/setup.py", line 18, in setup
Glabel1 = tk.Label(Groot, text=prompt, width=len(prompt), bg='yellow')
NameError: name 'Groot' is not defined

As I mentioned, I can get this to work by passing 'Groot' as a parameter to setup.setup(), but how can I use 'Groot' as a global WITHOUT having to pass it as a parameter?

Thank you for any and all comments, suggestions, and assistance in this effort.

Blessings in abundance, all the best, & ENJOY!
Art in Carlisle, PA USA

[metulburr]

Without passing as a parameter... i would say to create your Groot within setup directly and pass that back to the main program then. Often you will have a settings file with static data that you import to many modules. You should be cautious to use globals so often.

setup.py

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# MODULE "setup.py" in moduletest import tkinter as tk   Groot = tk.Tk()    def setup():     # Create and load the display label into the window     prompt = '        Press any key        '     Glabel1 = tk.Label(Groot, text=prompt, width=len(prompt), bg='yellow')     Glabel1.pack()     return Groot

main program

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import setup #<- imports go at top ... #Groot = tk.Tk()  # Create the GLOBAL root window Glabel1 = []     # Global Label identifier GCOUNT = 0       # Global Keystroke counter      # Create and load the display label Groot = setup.setup() ...

[Webtest]

Thanks metulburr!
Your suggestion looks reasonable and your advice is sound. I did a LOT of searching, and did find MANY caveats regarding Globals. However, I did also find the following ELEGANT and sanctioned solution, which works great for my program:

Python Software Foundation
Programming FAQ: How do I share global variables across modules?

It is very brief and is well worth looking at. Basically, you just put all the Globals in a "config.py" file. That puts them all in a single file in their own namespace ... I use "import config as G", so each Global is "G.name". Without this I would be passing TONS of stuff ... 3 arrays of 65 widgets each, a dictionary of complex dynamic widget formats, and many other variables. Each of the FIVE steps of the State Machine manipulates them differently.

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# Module config.py Root = []       # Global Window identifier Label1 = []     # Global Label identifier Count = 0       # Global Keystroke counter

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# Module Test for Globals and Modules import tkinter as tk import config as G import setup    G.Root = tk.Tk()  # Create the GLOBAL root window   # Create and load the display label setup.setup()    # #########  Keyboard 'Keypress' event handler  ######### def key(event):     G.COUNT += 1     msg = '%d %r %d %d' %(G.COUNT,event.keysym,event.keysym_num,event.state)     print(msg) # #######################################################    # Bind the Keypress event to the 'key' event handler G.Root.bind_all('<Key>', key) # Exit to the running event-driven app G.Root.mainloop()

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# MODULE "setup.py" in moduletest import tkinter as tk import config as G    def setup():     # Create and load the display label into the window     prompt = '        Press any key        '     G.Label1 = tk.Label(G.Root, text=prompt, width=len(prompt), bg='yellow')     G.Label1.pack()   #  <-- pack/grid MUST be on separate line !!!     return

Blessings in abundance, all the best, & ENJOY!
Art in Carlisle, PA USA

[snippsat]

I did also find the following ELEGANT and sanctioned solution, which works great for my program:

It may work,buy is far from great
There is a reason why classes is almost always used and preferred in GUI programming.
Then there is no use of Globals ,self act like magic transporter of values.
So a basic example with a class from doc,if i put in counter as you have it then it look like this.
See that there is no Global used to make this counter.

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import tkinter as tk   class Application(tk.Frame):     def __init__(self, master=None):         super().__init__(master)         self.master = master         self.button_clicks = 0         self.pack()         self.create_widgets()       def create_widgets(self):         self.hi_there = tk.Button(self)         self.hi_there["text"] = "Click me"         self.hi_there["command"] = self.say_hi         self.hi_there.pack(side="top")         self.quit = tk.Button(self, text="QUIT",fg="blue",command=self.master.destroy)         self.quit.pack(side="bottom")       def say_hi(self):         self.button_clicks += 1         print(f"hi there,you have clicked {self.button_clicks} times now")   root = tk.Tk() app = Application(master=root) app.mainloop()