[R] Automatizing Simulation in R

[Don MacQueen]

I often use the paste() and assign() approach that David suggested.
Another approach is to read into R a vector of file names and then 
loop over that vector.
Along the lines of:

infiles <- list.files(pattern='data*.dat')
dlist <- list()
length(dlist) <- length(infiles)
names(dist) <- infiles

for (inf in infiles) {
     tmpd <- read.table(inf,  *other args*)

    ## if you need to keep copies within R of all 500 sets of data
     dlist[[inf]] <- tmpd

     ## data analasyis using tmpd or dlist[[inf]]

}

-Don

At 10:22 AM -0500 11/12/09, David Winsemius wrote:
>On Nov 12, 2009, at 8:42 AM, Jeff Harring wrote:
>
>>I have a question regarding automatizing simulation runs in R...
>
>>
>>I have 500 external data sets for a simulation study that I would 
>>like to bring into R to analyze. They have the names data1.dat, 
>>data2.dat, ..., dataN.dat
>>
>>Is there a way to automatize the bringing in of these data sets in 
>>R using the read.table function within a looping cycle?
>>
>>For example...
>>
>>for (j in 1:N){
>>data_"j" = read.table("data"j".dat, header=F)
>
>Perhaps something like this:
>
>for (j in 1:N){
>assign(paste("data", j, sep="_") ,  read.table( 
>paste("data",j,".dat", sep=""), header=F) }
>
>
>Or even better might be to assign to a list which would augmentalize 
>your future automatizabilationabilty:
>
>flist <- list()
>for (j in 1:N){
>flist[[j]] <- read.table( paste("data",j,".dat", sep=""), header=F) }
>
>--
>David
>>executable code
>>.
>>.
>>.
>>}
>>
>>bring in the next data set.
>>
>>SAS uses a ampersand "&" to automatize the process.
>>
>>Example code:
>>
>>data _NULL_;
>>  set final;
>>      filename out "C:\data&k..dat";
>>      file out;
>>      put variables;
>>run;
>>
>>I would welcome any insight into how to address this issue.
>>
>>Thank you.
>>Jeff Harring
>>
>>--
>>**********************************************************
>>Jeffrey R. Harring, Assistant Professor
>>Department of Measurement, Statistics & Evaluation (EDMS)
>>1230 Benjamin Building
>--
>
>David Winsemius, MD
>Heritage Laboratories
>West Hartford, CT
>
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-- 
--------------------------------------
Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA
925-423-1062