CODEWITHSUNDEEP
pythonpython-3.xvalidationtkintertkinter-entry
Parviz Karimli
Parviz Karimli

Reputation: 1287

Similar validation functions don't work

First of all, sorry for not using OOP, I just decided to avoid complexity for such a small program. So here's my program (basically, it's an Entry widget that allows a text that only consists of integers whose maximum length is 5):

from tkinter import *
root = Tk()
root.title("Entry Validation")
root.geometry("300x100")

def validation_function(text):
    if len(text) <= 5:
        try:
            text = int(text)
            return True
        except:
            return False
    else:
        return False

vcmd = root.register(validation_function)
entry = Entry(root, validate='key', validatecommand=(vcmd, "%P"))
entry.pack()

It works normal. But when I make a little change in the body of the validation function, it doesn't work:

def validation_function(text):
    try:
        text = int(text)
        if len(text) <= 5:
            return True
        else:
            return False
    except:
        return False

I feel the problem is here:

except:
    return False

Probably the max length part doesn't go well with try-except... However:

def validation_function(text):
    try:
        if len(text) <= 5:
            return True
        else:
            return False
    except:
        return False

works correctly. But there is only the max length part, I also want it to allow only integers. I've done it in the first example, but my question is: why doesn't it work when I change the places of the max length part with the only integers part?

Upvotes: 0

Views: 52

Answers (1)

Joran Beasley
Joran Beasley

Reputation: 113940

text is an int ... you cannot call len(int) ... it will raise an exception

try this

def validation_function(text):
    try:
        int(text)
    except:
        return False
    if len(text) <= 5:
        return True
    return False

Upvotes: 3

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