From: David Barron <mothsailor_at_googlemail.com>

Date: Sun, 17 Jun 2007 23:05:22 +0100

Date: Sun, 17 Jun 2007 23:05:22 +0100

I'm not sure I've completely understood this, but would this do what you want:

output <- by(c, aa, function(x) sum(x$b))

output.matrix[,i] <- as.vector(output)

}

On 17/06/07, Economics Guy <economics.guy_at_gmail.com> wrote:

> Based on help files and searching the archives and help from the listserv I

*> have managed to build my monte carlo program.
**>
**> However I cannot get the proper syntax for running the loop and storing the
**> output of each loop (which is a vector) into a matrix.
**>
**> I took out some of the crazy code I was writing, but here is what I have:
**>
**> --------------------
**>
**> rm(list = ls(all = TRUE))
**> # removes everything
**>
**> a <-c("A","C","B","A","B","C")
**>
**> b <-c(10,20,30,40,50,60)
**>
**> c <-data.frame(a,b)
**>
**> N=10 #Number of Loops
**>
**> output.matrix <- matrix(0.0,3,N)
**>
**> #I need to START LOOP HERE
**>
**> a <- sample(a, replace=TRUE)
**>
**> c <-data.frame(b,a)
**>
**> output.vector <- by(c, a, function(x) sum(x$b))
**>
**> output.vector <- as.vector(output)
**>
**> output.vector <- data.frame(output)
**>
**> #END LOOP here
**>
**>
**> --------------------------
**>
**> What I would like to have at the end is the "output.matrix" contain as a
**> column the "output.vector" from each iteration. The actual data frame I
**> will be running has 60,000 observations and I am going to run 20000
**> iterations so speed is important too.
**>
**> Thanks so much
**>
**> EG
**>
**> [[alternative HTML version deleted]]
**>
**> ______________________________________________
**> R-help_at_stat.math.ethz.ch 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.
**>
*

-- ================================= David Barron Said Business School University of Oxford Park End Street Oxford OX1 1HP ______________________________________________ R-help_at_stat.math.ethz.ch 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.Received on Sun 17 Jun 2007 - 22:18:32 GMT

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