[R] Macro variable substitution

Greg Snow Greg.Snow at imail.org
Wed Sep 30 18:28:51 CEST 2009


There was a rather in depth article on doing macros in R in the R newsletter a couple of years ago.  There is also the defmacro function in the gtools package based on that article that can make the job easier for many cases.

See fortune(236) before taking the assign route.

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of David Young
> Sent: Tuesday, September 29, 2009 9:58 AM
> To: r-help at r-project.org
> Subject: [R] Macro variable substitution
> 
> Hello All,
> 
> I'm a new R user and have a question about what in SAS would be called
> macro variable substitution.  Below is some R code that doesn't work,
> but I think it will illustrate what I'd like to do.
> 
> readfunc<-function(x) {
>   x <<- read.table(paste(x,".csv",sep=""), header=TRUE,sep=",")
> }
> readfunc(TEF)
> 
> What I'd like to do is have the letters "TEF" become the name of the
> new
> R data and also be used in conjunction with ".csv" to read the file
> "TEF.csv".
> 
> So working R code looks like this:
> 
> TEF <- read.table(TEF.csv, header=TRUE,sep=",")
> 
> but I'd like to type the changing letter sequence just once.
> 
> Any suggestions would be appreciated.
> 
> --
> Best regards,
> 
> David Young
> Marketing and Statistical Consultant
> Madrid, Spain
> +34 913 540 381
> http://www.linkedin.com/in/europedavidyoung
> 
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