I have this code python, while running the code does not show any error but when Please click on the button does not show the result

Question

from tkinter import *

root = Tk()

def cal():
    l=[15,7,9,11]
    s=0
    for i in range(0,len(l)):
        s=s+l[i]
return s

b = Button(root, text="ok", command=cal())
b.pack()

label = Label(root, text=cal())
label.pack()

root.mainloop()

what is the callback function supposed to do? – Padraic Cunningham Sep 21 '15 at 13:58 — Padraic Cunningham, Sep 21 '15 at 13:58

score 0 · Answer 1 · answered Sep 21 '15 at 13:56

0

You need to store a reference to the function command=cal instead of storing the function's return value command=cal().

answered Sep 21 '15 at 13:56

Morgan Thrapp

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@KumarPyth: Hello? It's written in the answer: `command=cal`. – Matthias Sep 21 '15 at 14:02
That still won't change th text, `st = StringVar();label = Label(root, textvariable=st)`, you can set the label in the callback function, `st.set(s)` – Padraic Cunningham Sep 21 '15 at 14:03
That's right of course. – Matthias Sep 21 '15 at 14:04
Oh yeah, op still has quite a few issues in their code, but this fixes the question in their post. The rest is left as an exercise to the reader. – Morgan Thrapp Sep 21 '15 at 14:06

I have this code python, while running the code does not show any error but when Please click on the button does not show the result

1 Answers1