[R] Question regarding if statement in while loop

[Stephanie Coffey]

Stephan, Patrick & Carl,
Thanks very much for your help...and during the holidays no less!

Putting my function within a try() worked perfectly!!

Happy New Year,
Stephanie

On Sat, Dec 26, 2009 at 1:38 PM, Stephan Kolassa <Stephan.Kolassa at gmx.de> wrote:
> Hi Stephanie,
>
> it sounds like R's exception handling may help, something like this:
>
> foo <- try(eblest(i, dir5, sterr5, weight5, aux5))
> if ( class(foo) == "try-error" ) next
>
> Take a look at ?try.
>
> HTH,
> Stephan
>
>
> Stephanie Coffey schrieb:
>>
>> Hi all,
>> I'm running R version 2.9.2 on a PC.
>>
>> I'm having a problem with a loop, and have tried using an if statement
>> within to fix it, but to no avail.
>> Any advice would be appreciated.
>>
>> Here is my code:
>> *****************************************************
>> eblest <- function(i,dir, sterr, weight, aux) {
>> n <- nrow(dir)
>> Y <- as.matrix(dir[,i], ncol=1)
>> sigma2ei <- as.matrix(sterr[,i]^2, ncol=1)
>> w <- as.matrix((weight[,3])*(sigma2ei), ncol=1)
>> X <- as.matrix(subset(aux, select=c(3,5:7,9:10,13)))
>> a <<- EBLUP.area(Y,cbind(w,1),sigma2ei,n)            #The EBLUP.area
>> function is a function already in R.
>> }
>>              # It gives a bunch of output, some of what I need.
>>
>> #THIS IS THE LOOP I'M HAVING A PROBLEM WITH:
>> results <- data.frame(length=nrow(dir5))
>> i <- 3
>> while (i <=some number) {
>> eblest(i, dir5, sterr5, weight5, aux5)
>> out <<- cbind(i, a$EBLUP, a$mse)
>> results <- cbind(results, out)
>> i <- i+1
>> }
>> ***********************************************************************
>> I have tried running the eblest function for a specific set of input
>> (i, dir5, etc as in the function) This function runs ok.
>> However, sometimes eblest does not create the expected output,
>> sometimes due to the solution being singular or other reasons.
>> I'm not so concerned about that at this point - it's a function of the
>> data.
>>
>> My problem is that, as you can see, after eblest runs, the "out"
>> pieces of information are bound together in the results matrix.
>> When the eblest does not run correctly, the loop stops.  For example,
>> when i=3 and i=4, eblest runs ok, and I get a maxtrix with the
>> following columns:
>>
>> i    EBLUP se.EBLUP i EBLUP se.EBLUP
>> 3           x                y    4        a                bh
>>
>> ...but when it loops back around to start i=5, I get an error because
>> the solution is singular.  But I don't want the loop to stop (I have
>> ~100 of these i's for which I need to execute this function.
>>
>> So I would like to set an if condition that will cause the loop to
>> step ahead (in this case, to 6), and continue looping...Something like
>> "if exists("out")=FALSE next, else..."  However, when I tried that,
>> the results matrix was empty created at all.
>>
>> In case it helps, "out" has a "numeric" mode, and is a "matrix"...
>>
>> I've written these functions and loops using online help and examples
>> I've found on websites, but clearly I'm missing something.
>>
>> Thanks for any help you can give!!
>>
>> ~Stephanie Coffey
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>