Calling a sequence of commands with a sequence of Tkinter buttons

[Harald Rosemann]

Martyn Quick wrote:
> 
> I'm trying to create a number of buttons each of which has a similar sort
> of command attached to it.  Obviously the following doesn't work since I'm
> attaching a called function to the button rather than the function to
> call.  Can anyone tell me the correct way to do it?  (Equally obviously, I
> could create a different function for each button, but this seems lengthy
> for a large number of buttons).
> 
> Thanks
> Martyn
> 
> MY ATTEMPT:
> 
> from Tkinter import *
> 
> def f(i):       # Typically I'll have a more complicated function
>         print i # but this is just for illustration
> 
> root = Tk()
> 
> buttons = []    # initialize list to contain the button widgets
> 
> for i in range(20):
>         buttons.append(Button(root,text="Button "+`i`,command=f(i)))
>         buttons[i].pack()
>         # This doesn't work - it just prints 1,2,..,20 down the screen
>         # immediately, since f(i) is called at the creation of the button.
> 
> 
> --------------------------------------------------------
> Dr. Martyn Quick  (Research Fellow in Pure Mathematics)
> University of Birmingham, Edgbaston, Birmingham, UK.
> http://www.mat.bham.ac.uk/M.R.Quick





You may use a "lambda expression". 
Something like the following will work.



def show_ind(i, event=None):
    print i
...

my_tst[i] = Tkinter.Frame(zzz, ....)
my_tst[i].pack()
....

my_but[i] = Tkinter.Button(my_tst[i], text = ".....", state = status)
my_but[i].pack(side = Tkinter.LEFT)
my_but[i].bind("<Button-1>", (lambda event, ind=i: show_ind(ind,
event)))


With best regards,
Harald Rosemann

-- 
Prof.Dr.-Ing. Harald Rosemann
am Institut fuer Maschinenelemente, 
   Konstruktionstechnik und Tribologie
Universitaet Hannover