How to pass arguments to a Button command in Tkinter?

Question

Suppose I have the following Button made with Tkinter in Python:

import Tkinter as Tk
win = Tk.Toplevel()
frame = Tk.Frame(master=win).grid(row=         


        

Answer 1

The reason it invokes the method immediately and pressing the button does nothing is that action(somenumber) is evaluated and its return value is attributed as the command for the button. So if action prints something to tell you it has run and returns None, you just run action to evaluate its return value and given None as the command for the button.

To have buttons to call functions with different arguments you can use global variables, although I can't recommend it:

import Tkinter as Tk

frame = Tk.Frame(width=5, height=2, bd=1, relief=Tk.SUNKEN)
frame.grid(row=2,column=2)
frame.pack(fill=Tk.X, padx=5, pady=5)
def action():
    global output
    global variable
    output.insert(Tk.END,variable.get())
button = Tk.Button(master=frame, text='press', command=action)
button.pack()
variable = Tk.Entry(master=frame)
variable.pack()
output = Tk.Text(master=frame)
output.pack()

if __name__ == '__main__':
    Tk.mainloop()

What I would do is make a class whose objects would contain every variable required and methods to change those as needed:

import Tkinter as Tk
class Window:
    def __init__(self):
        self.frame = Tk.Frame(width=5, height=2, bd=1, relief=Tk.SUNKEN)
        self.frame.grid(row=2,column=2)
        self.frame.pack(fill=Tk.X, padx=5, pady=5)

        self.button = Tk.Button(master=self.frame, text='press', command=self.action)
        self.button.pack()

        self.variable = Tk.Entry(master=self.frame)
        self.variable.pack()

        self.output = Tk.Text(master=self.frame)
        self.output.pack()

    def action(self):
        self.output.insert(Tk.END,self.variable.get())

if __name__ == '__main__':
    window = Window()
    Tk.mainloop()