[R] How should i change the SAS Codes into R Codes?

[Matt Aldridge]

singleSim <- expand.grid(se = 0:100/100, sp = 0:100/100, DR = 0:100/100)
singleSim <- within(singleSim, {
	TR <- (DR+sp-1)/(se+sp-1+1.0e-12)
	AdjustFactor <- TR/(DR+1.0e-12)
})
sampleData <- subset(singleSim, DR == .02 & sp == 1)
write.csv(sampleData, "output.csv") 

Hope this helps

Matt
mangosolutions - R and S consultants
Tel   +44 (0)1249 767700 


-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of zhijie zhang
Sent: 27 July 2009 16:04
To: r-help at stat.math.ethz.ch
Subject: [R] How should i change the SAS Codes into R Codes?

Dear R users,
  I have a SAS codes with several loops in it, and i hope to use R to do
the
same task. The SAS codes are as follows,
/*to generate the dataset*/
DATA Single_Simulation;
 DO se=0 to 1 by 0.01;
  DO sp=0 to 1 by 0.01;
   DO DR=0 to 1 by 0.01;
    TR=(DR+sp-1)/(se+sp-1+1.0e-12);
    Adjust_Factor=TR/(DR+1.0e-12);
    OUTPUT;
   END;
  END;
 END;
RUN;

/*to select some data*/
DATA sampledata;
 SET Single_Simulation;
 IF DR=0.02 & sp=1;
RUN;

#I tried the following codes with R,failed
num<-seq(0, 1, by = 0.01)
for (se in num) {
 for (sp in num) {
   for (DR in num) {
    TR=(DR+sp-1)/(se+sp-1+1.0e-12)
    Adjust_Factor=TR/(DR+1.0e-12)
  }
 }
}

My questions are,
1. What is the correct codes for R to do the similar task?
2. Sometimes, the simulated dataset are very large, so i need to put the
generated dataset in a file with large disk place, not in the memory,
how to
do it? SAS can do it with the 'libname' argument,  do R have the similar
method?
  Thanks a lot.

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