[Tkinter] Python Newbie - Printable Version

[Tkinter] Python Newbie - Printable Version

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Python Newbie - MartyH - May-11-2020

Hi guys,

I hope you can helpppppp.....

I have a program which is supposed to get the new values of 9 variables.

It initializes [init()] by arranging the numbers similar to a spreadsheet, and putting varaibles in the "textvariable" as var00, var01, var02 etc

Then it give values to each by attempting to use the .get method of the Control variables.

But my program does not work.
Thanks
Marty

import tkinter as tk
from tkinter import *

root = tk.Tk()

def give_values():
    # row 0
    var00 = StringVar().get()
    var01 = StringVar().get()
    var02 = StringVar().get()
    # row 1
    var10 = StringVar().get()
    var11 = StringVar().get()
    var12 = StringVar().get()
    # row 2
    var20 = StringVar().get()
    var21 = StringVar().get()
    var22 = StringVar().get()
    v = (var00, var01, var02, var10, var11, var12, var20, var21, var22)
    print(v)

def init():
    for i in range(3):
        for j in range(3):
            frame = tk.Frame(
                master=root,
                relief=tk.RAISED,
                width=2,
                borderwidth=1
            )
            frame.grid(row=i, column=j)
            entry = tk.Entry(master=frame,
                             text=f"Row {i}\nColumn {j}",
                             textvariable="var" + str(i) + str(j))
            entry.pack()


give_values()
init()
give_values()
# b1 = Button(root, text="Done", width=10).grid(row=0, column=10, rowspan=10)  # command=done)
b2 = Button(root, text="Enter", width=10, command=give_values).grid(row=1, column=10, rowspan=10)  # command=enter())

root.mainloop()

RE: Python Newbie - MartyH - May-12-2020

Thanks for changing the location of my post to the correct one! I am ready to throw in the towel -- i've tried everything that I know -- I'm using python 3.7.3 Is there anything else I can add?

Thanks marty

RE: Python Newbie - deanhystad - May-12-2020

A couple of problems here. You are creating new StringVars every time you call give_values so there is no way these can be bound to an Entry. Even if you only created the StringVar's once, their attribute names (varXX) do not exist outside the function give_values, so you would have no way to get these variables and bind them to the entries. Finally, you cannot set textvariable="var00" and expect the Entry constructor to figure out which namespace to use to search for attribute "var00" and get a StringVar.

import tkinter as tk
from tkinter import *
 
root = tk.Tk()
variables = []

def give_values():
    return [var.get() for var in variables] # Makes a list calling get for each StringVar in variables
 
def init():
    for i in range(3):
        for j in range(3):
            frame = tk.Frame(
                master=root,
                relief=tk.RAISED,
                width=2,
                borderwidth=1
            )
            frame.grid(row=i, column=j)
            var = StringVar()
            variables.append(var)
            entry = tk.Entry(master=frame,
                             text=f"Row {i}\nColumn {j}",
                             textvariable=var)
            entry.pack()
 
 
init()
# b1 = Button(root, text="Done", width=10).grid(row=0, column=10, rowspan=10)  # command=done)
b2 = Button(root, text="Enter", width=10, command=give_values).grid(row=1, column=10, rowspan=10)  # command=enter())
 
root.mainloop()

RE: Python Newbie - MartyH - May-13-2020

that's great and i am part of the way there -- I really appreciate that! I still have 2 questions:

1) I really didn't understand StringVar, and I am not sure that really do now!! Perhaps you can expand on it!

2) Another question --> so now I've got a list of <tkinter.StringVar object at 0x00F68290>, ... etc how does this translate into the value for the variable? I have tried all sorts of machinations of [variables] and can't seem to get any satifaction.

Thanks,
Marty

RE: Python Newbie - buran - May-13-2020

this is old, bit outdated tutorial on tkinter, but still one of the best:
https://anzeljg.github.io/rin2/book2/2405/docs/tkinter/index.html
this is the part about control variables:
https://anzeljg.github.io/rin2/book2/2405/docs/tkinter/control-variables.html

RE: Python Newbie - deanhystad - May-13-2020

A short example using most of your provided code:

import tkinter as tk
from tkinter import *
  
root = tk.Tk()
variables = []
 
def increment():
    for i in range(len(variables)-1):
        variables[i].set(variables[i+1].get())
    variables[-1].set(variables[-1].get() + 1)
    
def init():
    for i in range(3):
        for j in range(3):
            frame = tk.Frame(master=root, relief=tk.RAISED)
            frame.grid(row=i, column=j)
            var = IntVar()
            variables.append(var)
            entry = tk.Entry(master=frame, width=3, textvariable=var)
            entry.pack()

    b2 = Button(root, text="Increment", command=increment) \
         .grid(row=3, column=0, columnspan=3)

init()
root.mainloop()

RE: Python Newbie - MartyH - May-13-2020

Hey that really helps!!
I've just discovered how line 19 related to the "Increment" method (by the line directly above it)
and I have to look at carefully to discover some other facts...
Thanks,

Marty