无法使用 Tkinter 中的输入框将字符串转换为整数

Question

i'm new to tkinter and python in general and i'm having an issue that i can't solve. In my program i want to take input from the user and transform it into an integer to use that variable later on. The main issue is that i get the error invalid literal for int() with base 10: ''. I tried different methods by searching online but none of them did work. Any help is well appreciated. Thank you! error message on visual studio

My code:

from tkinter import *
import tkinter as tk
window = Tk()

window.title("Controlla quote")
window.geometry('400x150')

#binari
binari_num=0
def binari(number):
    if number==1:
        binari_num=1
        print("binari= ",binari_num)
    elif number==2:
        binari_num=2
        print("binari= ",binari_num)
    else:
        pass
    return binari_num
#radiobuttons
info = IntVar()
binari_1 = Radiobutton(window, text="1", command=lambda:binari(info.get()),variable=info,value=1).grid(column=1, row=0)
binari_2 = Radiobutton(window, text="2", command=lambda:binari(info.get()),variable=info,value=2).grid(column=2, row=0)
#binari label
binari_scritta=Label(window, text="Binari:").grid(column=0, row=0, stick=W)

#stazionamenti
stazionamenti_label=Label(window, text="Stazionamenti: ").grid(column=0, row=1, stick=W)
stazionamenti_entry=Entry(window)
stazionamenti_entry.grid(column=1, row=1, stick=W)
#conversion stazionamenti
stazionamenti_str= stazionamenti_entry.get()
stazionamenti_num= int(stazionamenti_str)


#avanti
def avanti():
    pass
avanti_btn=Button(window, text="Avanti", command=avanti()).grid(columnspan=50, stick=E)

window.mainloop()

Answer 1

The problem is that the code gets executed right away and when stazionamenti_entry.get() is called, its basically an empty string "" . int() requires a valid string which contains only numbers and a minus sign at first place optionally. Strings with spaces or empty string or with non numerical characters give this error.

The error means "the string provided is not convertable to int".

What you can do is make a function and call it when stazionamenti_entry.get() is needed and make sure there is numeral data in stazionamenti_entry . More precisely you should do it in you avanti function.

You can add in some checks before stazionamenti_num= int(stazionamenti_str) like:

if stazionamenti_str :
    stazionamenti_num= int(stazionamenti_str)

This will make sure that string is not empty.

On OPs request:

.
.
.
stazionamenti_label=Label(window, text="Stazionamenti: ").grid(column=0, row=1, stick=W)
stazionamenti_entry=Entry(window)
stazionamenti_entry.grid(column=1, row=1, stick=W)
#conversion stazionamenti


def helper():
    global stazionamenti_num
    global stazionamenti_entry
    if stazionamenti_entry.get():
        stazionamenti_num = int(stazionamenti_entry.get())
#avanti
def avanti():
    helper()
    print(stazionamenti_num)

avanti_btn=Button(window, text="Avanti", command=avanti).grid(columnspan=50, stick=E)
window.mainloop()

Answer 2

Can you try

binari_1 = Radiobutton(window, text="1", command=lambda:binari(int(info.get())),variable=info,value=1).grid(column=1, row=0)

binari_2 = Radiobutton(window, text="2", command=lambda:binari(int(info.get())),variable=info,value=2).grid(column=2, row=0)

I think the IntVar() seems to have a different approach or object being returned. Try converting it using int() function

Answer 3

I ended with this. But if i print(stazionamenti_num) it does not print it @abdullahQureshee

#stazionamenti
stazionamenti_label=Label(window, text="Stazionamenti: ").grid(column=0, row=1, stick=W)
stazionamenti_entry=Entry(window)
stazionamenti_entry.grid(column=1, row=1, stick=W)
#conversion stazionamenti
global stazionamenti_str
global stazionamenti_num
stazionamenti_str=""
def stazionamenti_convert():
    stazionamenti_num= int(stazionamenti_str)


#avanti
def avanti():
    if stazionamenti_str:
        stazionamenti_convert()
avanti_btn=Button(window, text="Avanti", command=avanti()).grid(columnspan=50, stick=E)
window.mainloop()