I think you need to spend some time with an R tutorial or two to learn how to handle such basics yourself.
However, if I understand correctly, probably the easiest way to do it is by converting a matrix of 0's to a data frame -- which you shouldn't do at all if you can do your analysis directly with the matrix (it's almost always faster, sometimes considerably so). e.g. adf <- data.frame(matrix(0, nrow=10,ncol=20)) Of course, you may then wish to provide more informative names for your columns via the names() function. Also, I would question whether you need to do any of this in the first place. It is rarely necessary in R to initialize a data frame or matrix. Finally, you should almost never need the eval(parse()) construction, which treats R as a macro language instead of taking advantage of its functional programming paradigm. Again, the of sort thing that good R tutorials can help you with. There are many on the web. Some good recommendations can be found here: https://www.rstudio.com/online-learning/#R HTH, Bert Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Mon, Apr 4, 2016 at 9:22 AM, Janszen, Derek <derek.jans...@precisionformedicine.com> wrote: > Hi, > > I want to create a data frame similar to the following, but greatly scaled up: > df <- data.frame(aaa= c("a","b","c"), integer(3), integer(3)) > names(df)[2:3] <- paste("var",1:2,sep="") > which yields > aaa var1 var2 > 1 a 0 0 > 2 b 0 0 > 3 c 0 0 > > I would not relish having to paste 'integer(3)' 5000 times :( > > So (I figure) there must be a way to do this programmatically, something akin > to > exp1 <- paste(rep("integer(3)",2),collapse=',') > which looks like it might work: "integer(3),integer(3)" , as in the > following > df <- data.frame(aaa=xxx, eval(parse(text=exp1))) > but this yields > > Error in parse(text = exp1) : <text>:1:11: unexpected ',' > > 1: integer(3), > > ^ > > > Not sure just why this doesn't work (?parse does not help), but it's not > important right now. > > I have used eval and parse in the past, but not in a way similar to what I'm > trying to do now. > > > > exp1 <- rep("integer(3)",2) gives "integer(3)" "integer(3)" > > and upon parse(text=exp1) gives expression(integer(3), integer(3)) > > which appears to be promising, and does not give an error in the following > > df <- data.frame(aaa=xxx, eval(parse(text=exp1))) > > but alas, does not give the desired result > aaa eval.parse.text...exp1.. > 1 a 0 > 2 b 0 > 3 c 0 > > > > > I'm guessing that only the last evaluation of the expression is being > evaluated, which I can understand. > > I feel certain that what I want to accomplish can be done programmatically, > but am at a loss as to just how to do that. > Chances are this has been covered before. If so, apologies. > If not, can anyone point me to references with more info than the help pages, > or suggest a solution? :) > > Thanks, > Derek > > Derek Janszen, PhD > Statistician, Analytics > > Precision for Medicine<http://www.precisionformedicine.com/> > 8425 Progress Drive, Suite M | Frederick, MD 21701 > +1 240 415 6004 office > > > > The information contained in this email and any attachments is confidential > and may be subject to copyright or other intellectual property protection. If > you are not the intended recipient, you are not authorized to use or disclose > this information, and we request that you notify us by reply mail or > telephone and delete the original message from your mail system. > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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 -- To UNSUBSCRIBE and more, see 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.
