Restricting the value in Tkinter Entry widget

Question

I need to restrict the values in the Entry widget to numbers only. The way I implemented is:

import numpy as np
from Tkinter import *;
import tkMessageBox;

         


        

Answer 1

if you are dealing with locales that have a comma as decimal point:

locale.setlocale(locale.LC_ALL,'de_DE.UTF-8') # German

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vcmd = (self.root.register(self.entry_numericonly), '%d', '%P')

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self.my_float_entry = tk.Entry(self.root, ... , validate='key', validatecommand=vcmd)

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def entry_numericonly(self, action, value_if_allowed):
    if(action == "1"):
        try:
            loc_float  = locale.atof(value_if_allowed)
            loc_float_format = locale.format("%f", loc_float)
            try:
                loc_same_length = loc_float_format[:len(value_if_allowed)]
                return value_if_allowed == loc_same_length
            except:
                return False                    
        except:
            return False
    else:
        return True