To access a variable by a character string name, try for(code in codes) { dat <- get(code) [stuff] }
Other options include ?assign if you need to manipulate the original, or ?with to use the subject of "codes" as an environment. -------------------------------------- Jonathan P. Daily Technician - USGS Leetown Science Center 11649 Leetown Road Kearneysville WV, 25430 (304) 724-4480 "Is the room still a room when its empty? Does the room, the thing itself have purpose? Or do we, what's the word... imbue it." - Jubal Early, Firefly r-help-boun...@r-project.org wrote on 02/25/2011 12:33:32 PM: > [image removed] > > Re: [R] Variable names AS variable names? > > Noah Silverman > > to: > > 02/25/2011 12:35 PM > > Sent by: > > r-help-boun...@r-project.org > > Cc: > > r-help > > My actual code is several things with adaptive filtering. This will > require accessing data sporadically. The loop was just a quick example > for the e-mail. > > One application is to work with online (streaming) data. If I get a new > data point in for code "a1", I'll need to be able to reference the > matrix named "a1". > > On 2/25/11 12:23 AM, David Winsemius wrote: > > > > On Feb 25, 2011, at 1:55 AM, Noah Silverman wrote: > > > >> How can I dynamically use a variable as the name for another variable? > >> > >> I realize this sounds cryptic, so an example is best: > >> > >> #Start with an array of "codes" > >> codes <- c("a1", "b24", "q99") > > > > Is there some reason not to use list(a1, b24, q99)? If not then: > > > > lapply(codes, somefun) > > > > > >> > >> #Each code has a corresponding matrix (could be vector) > >> a1 <- matrix(rnorm(100), nrow=10) > >> b24 <- matrix(rnorm(100), nrow=10) > >> q99 <- matrix(rnorm(100), nrow=10) > >> > >> #Now, I want to loop through all the codes and do something with each > >> matrix > >> for(code in codes){ > >> #here is where I'm stuck. I don't want the value of code, but the > >> variable who's name is the value of code > >> > >> } > >> > >> > >> Any suggestions? > >> > >> -N > >> > >> ______________________________________________ > >> R-help@r-project.org 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 Winsemius, MD > > West Hartford, CT > > > > ______________________________________________ > R-help@r-project.org 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. ______________________________________________ R-help@r-project.org 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.