Python

tkinter button widget - passing parameter to function

Please support our Python advertiser: Programming Forums - DaniWeb Sister Site

•

Join Date: Feb 2008

Posts: 1

Reputation: rude_god is an unknown quantity at this point

Solved Threads: 0

rude_god

Offline

Newbie Poster

tkinter button widget - passing parameter to function

Jan 7th, 2009

Hi all

I've been messing about with this bit of code. Basically what it's
supposed to do is create these six buttons, which when clicked pass a parameter to a function and then call that function. The function basically removes one condition from a larger list depending on which button is clicked The problem is that the way I've written it, the functions runs automatically before the user actually clicks the button.

[code = python]
firstCond = ''
condNames = ['1', '2', '3', '4', '5', '6']
for item in condNames:
button = Button(frame, name = str(item), text = str(item), command = getCond(item)).pack()
def getCond(par):
firstCond = par
conditions.remove(firstCond)
print firstCond
print conditions
[/code]

So I want the function to run when the button is clicked, not automatically on its own. Now I know that the reason it does this is because of the brackets following getCond(item). However, I cannot see any other way of passing the parameter to the function.

Obviously, I could make separate functions for each condition, but I'm just wondering if I could do it more elegantly in this way? It would be a pain if I had 100 conditions instead of 6...

•

Join Date: Oct 2006

Posts: 2,297

Reputation: sneekula has a spectacular aura about

Solved Threads: 178

sneekula

Offline

Nearly a Posting Maven

Re: tkinter button widget - passing parameter to function

Jan 7th, 2009

Here is an example how to use lambda to pass arguments in Tkinter's button command:

 Help with Code Tags 
 python Syntax (Toggle Plain Text) 
import Tkinter as tk
 
def getCond(par):
    firstCond = par
    #conditions.remove(firstCond)
    print firstCond
    #print conditions
 
 
root = tk.Tk()
 
firstCond = ''
 
condNames = ['1', '2', '3', '4',  '5', '6']
for item in condNames:
    # use lambda to pass arguments to command-function
    tk.Button(root, text=str(item), command=lambda i=item: getCond(i)).pack()
 
root.mainloop()
import Tkinter as tk

def getCond(par):
    firstCond = par
    #conditions.remove(firstCond)
    print firstCond
    #print conditions


root = tk.Tk()

firstCond = ''

condNames = ['1', '2', '3', '4',  '5', '6']
for item in condNames:
    # use lambda to pass arguments to command-function
    tk.Button(root, text=str(item), command=lambda i=item: getCond(i)).pack()

root.mainloop()

Also, create your function before you call it.