From: Economics Guy <economics.guy_at_gmail.com>

Date: Sun, 17 Jun 2007 23:26:27 -0400

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 Mon 18 Jun 2007 - 03:38:14 GMT

Date: Sun, 17 Jun 2007 23:26:27 -0400

Thanks so much to both of you. I did not exactly use the code from either of you but your post help me figure out the things I was doing wrong.

For anyone who stumbles upon this thread later, here is the code I used that made it work:

Thanks Again.

a <-c("A","C","B","A","B","C")

b <-c(10,20,30,40,50,60)

d <-data.frame(a,b)

N=10 #Number of Loops

output.matrix <- matrix(0.0,3,N)

#I need to START LOOP HERE

for (i in 1:N){

a <- sample(a, replace=FALSE)

d <-data.frame(b,a)

output.vector <- by(d, a, function(x) sum(x$b))

output.vector <- as.vector(output.vector)

output.vector <- data.frame(output.vector)

output.vector <- as.vector(output.vector) #test

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

}

On 6/17/07, jim holtman <jholtman_at_gmail.com> wrote:

*>
*

> I think this does it for you:

*>
**> > a <-c("A","C","B","A","B","C")
**> >
**> > b <-c(10,20,30,40,50,60)
**> >
**> > C <-data.frame(a,b) # don't use 'c' as it is a primitive function -
**> canbe confusing
**> >
**> > N=10 #Number of Loops
**> >
**> >
**> >
**> > output.matix <- replicate(N, function(x){
**> + .samp <- C[sample(nrow(C), replace=TRUE), ]
**> + tapply(.samp$b, .samp$a, sum)
**> + })
**> > # transpose if you want samples in columns
**> > output.matrix <- t(output.matrix)
**> > output.matrix
**> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
**> A 10 130 100 40 50 40 30 50 50 50
**> B 130 60 50 110 100 160 110 130 60 150
**> C 40 NA 60 80 120 60 NA 60 80 20
**> >
**>
**>
**>
**> On 6/17/07, 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.
**> >
**>
**>
**>
**> --
**> Jim Holtman
**> Cincinnati, OH
**> +1 513 646 9390
**>
**> What is the problem you are trying to solve?
*

[[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. Received on Mon 18 Jun 2007 - 03:38:14 GMT

Archive maintained by Robert King, hosted by
the discipline of
statistics at the
University of Newcastle,
Australia.

Archive generated by hypermail 2.2.0, at Mon 18 Jun 2007 - 04:32:20 GMT.

*
Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help.
Please read the posting
guide before posting to the list.
*