R help - Feb 2012 - tcl tk command function with arguments ??

Hello, I am using R 2.11.1 under Windows XP.

I would like to know if its possible to use a function with arguments as a
command in tcl tk. For example

require(tcltk)
PressedOK <- function()
{
    tkmessageBox(message="You pressed OK!")
}

tt <- tktoplevel()
OK.but <- tkbutton(tt,text="OK",command=PressedOK)
tkgrid(OK.but)
tkfocus(tt)

the function PressedOK has no arguments and its use in
"tkbutton(tt,text="OK",command=PressedOK)" is without any
brackets.
Unfortunately I would like to use several buttons and therefor define the
corresponding functions to it.

For example


require(tcltk)
OK.but <- NULL
PressedOK <- function(i)
{
    tkmessageBox(message=paste("You pressed OK!",i,sep=""))
}

tt <- tktoplevel()
for(i in seq(3)){
	OK.but[[i]] <-
tkbutton(tt,text="OK",command=function()PressedOK(i))
	tkgrid(OK.but[[i]])
}
tkfocus(tt)

In this case, all buttons have the command of PressedOK(i) and therefore its
is always written "You pressed OK! 3" even if you push button 1. I
think
this is due to the fact that the PressedOK(3) was the last call of the
function, but I don't understand why all the other buttons have now a
different command. Any idea?

Thanks


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On Fri, Feb 24, 2012 at 12:58 AM, Alexander <juschitz_alexander at
yahoo.de> wrote:
> I would like to know if its possible to use a function with arguments as a
> command in tcl tk.
Yes

<snip>
 I think
> this is due to the fact that the PressedOK(3) was the last call of the
> function, but I don't understand why all the other buttons have now a
> different command. Any idea?
>
Because in for loop i is overwritten every time - as you said i=3 is
the last command.
Replacing for with sapply should fix it:

require(tcltk)
OK.but <- NULL
PressedOK <- function(i)
{
   tkmessageBox(message=paste("You pressed OK!",i,sep=""))
}

tt <- tktoplevel()
sapply(1:3,function(i){
  OK.but[[i]] <-
tkbutton(tt,text="OK",command=function()PressedOK(i))
  tkgrid(OK.but[[i]])
})
tkfocus(tt)

Cheers,
Elai

> Thanks
>
>
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>
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