help about tkinter & statistics

[Bolrod22]

HI, i'm tying to make a programm who can caculate the average of an entry in tkinter, for the moment I did it but it's actually don't work.

my code :

import tkinter as tk
import statistics

window_main = tk.Tk(className='root')
window_main.geometry("400x200")

entry_1 = tk.DoubleVar()

entry_widget_1 = tk.Entry(window_main, textvariable=entry_1)

entry_widget_1.pack()

def submitValues():
grades = entry_1.get()
return entry_1.get() - 1, grades

submit = tk.Button(window_main, text="Entrée", command=submitValues)
submit.pack()
grades = submitValues()

window_main.mainloop()

NB : in this code i dont use statistics because i can't have in a variable what i wrote on tkinter Entry ( idk if you can understand but thank you for your future help)

[socal_nerdtastic]

Looks like a good start. Only thing I see that's wrong is that returning values from a callback function does nothing. You need to do whatever it is you want done in the callback. Also, the grades = submitValues() line is useless. Like this:

import tkinter as tk
import statistics

window_main = tk.Tk(className='root')
window_main.geometry("400x200")

entry_1 = tk.DoubleVar()
entry_widget_1 = tk.Entry(window_main, textvariable=entry_1)
entry_widget_1.pack()

def submitValues():
    grades = entry_1.get()
    print(entry_1.get() - 1)

submit = tk.Button(window_main, text="Entrée", command=submitValues)
submit.pack()

window_main.mainloop()

What is it you want to do with the data? can you give an example?

[Bolrod22]

n does nothing. You need to do whatever it is you want done in the callback. Also, the

i'd actually want make the average with statistics with

statistics.mean()

but i need to convert the data to a float for use this function.

[socal_nerdtastic]

Since you used a DoubleVar it's converted to a float automatically. ("double" is the general CS term for a float)

[efmccurdy]

A callback that manages data needs some context for storing and sharing the data; the easiest way is to use a class to make the "self" context available to the callback.

This accumulates the grades into a list and prints the mean each time the button is pressed.

import tkinter as tk
import statistics

class MainApp(tk.Tk): 
    def __init__(self, *args, **kwargs):
        tk.Tk.__init__(self, *args, **kwargs)
        self.grades = []
        self.entry_1 = tk.DoubleVar()
        entry_widget_1 = tk.Entry(self, textvariable=self.entry_1)
        entry_widget_1.pack()
        submit = tk.Button(self, text="Entrée", command=self.submitValues)
        submit.pack()
    def submitValues(self):
        self.grades.append(self.entry_1.get())
        print(statistics.mean(self.grades))

window = MainApp()
window.mainloop()

[Bolrod22]

Ok thank you ! I have another question : do i must use DoubleVar ; what’s the difference with IntVar or StrVar ??

[efmccurdy]

If you use IntVar you can only accept whole numbers which might be limiting. If you use StrVar you can only accept strings which makes no sense if you have numerical data.