R help - Jul 2007 - Passing equations as arguments

Friends,

I'm trying to pass an equation as an argument to a function. The idea is as
follows. Let us say i write an independent function

Ideal Situation:

ifunc <- function(x)
{
return((x*x)-2)
}

mainfunc <- function(a,b)
{
evala <- ifunc(a)
evalb <- ifunc(b)
if (evala>evalb){return(evala)}
else
return(evalb)
}

Now I want to try and write this entire program in a single function with the
user specifying the equation as an argument to the function.

myfunc <- function(a, b, eqn)
{
    func1 <- function (x) ??????????????????
        {
            return(eqn in terms of x)  ??????????????????
       }

Further arguments to check

The ???????? imply that this does not seem to be correct. The idea is how to
assign the equation expression from the main equation into the inner function.
Is there anyway to do that within this set up?
 

Thanks in advance
Regards

Anup

       
---------------------------------

	[[alternative HTML version deleted]]

Here is one possible solution:

ifun <-
function(a, b, FUN){
    evala <- FUN(a)
    evalb <- FUN(b)
    if (evala > evalb) return(evala) else return(evalb)
}
ifun(1,2,function(x) (x*x) - 2)



On 7/24/07, Anup Nandialath <anup_nandialath at yahoo.com>
wrote:
> Friends,
>
> I'm trying to pass an equation as an argument to a function. The idea
is as follows. Let us say i write an independent function
>
> Ideal Situation:
>
> ifunc <- function(x)
> {
> return((x*x)-2)
> }
>
> mainfunc <- function(a,b)
> {
> evala <- ifunc(a)
> evalb <- ifunc(b)
> if (evala>evalb){return(evala)}
> else
> return(evalb)
> }
>
> Now I want to try and write this entire program in a single function with
the user specifying the equation as an argument to the function.
>
> myfunc <- function(a, b, eqn)
> {
>    func1 <- function (x) ??????????????????
>        {
>            return(eqn in terms of x)  ??????????????????
>       }
>
> Further arguments to check
>
> The ???????? imply that this does not seem to be correct. The idea is how
to assign the equation expression from the main equation into the inner
function. Is there anyway to do that within this set up?
>
>
> Thanks in advance
> Regards
>
> Anup
>
>
> ---------------------------------
>
>        [[alternative HTML version deleted]]
>
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http://www.R-project.org/posting-guide.html
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>

-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?