在python3中使用tkinter时，如何在每次按下函数时获得运行该函数的按钮？

Question

import tkinter as tk
panel = tk.Tk()
num = 42
lbl1 = tk.Label(panel, text = str(num))

假设我有这样一个函数和按钮：

def increase():
    lbl1.configure(text = str(num+1))

btn = tk.Button(panel, text = 'Increase', command = increase)

panel.mainloop()

按下按钮时，此按钮将使标签编号增加1。但是，在按钮完全不起作用之前，这只起作用一次。我怎样才能使每次按下按钮，数字都增加1？你知道吗

Answer 1

因为num总是43岁

import tkinter as tk
num = 42

def increase():
    global num
    num += 1
    lbl1.configure(text = str(num))


panel = tk.Tk()

lbl1 = tk.Label(panel, text = str(num))
lbl1.pack()
btn = tk.Button(panel, text = 'Increase', command = increase)
btn.pack()
panel.mainloop()

Answer 2

您从未保存num的增量值。你知道吗

def increase():
    global num # declare it a global so we can modify it
    num += 1 # modify it
    lbl1.configure(text = str(num)) # use it