Thanks very much for your detailed reply to my post. Very helpful/useful tool(s) you’ve provide me. Best wishes, B.
From: William Dunlap [mailto:wdun...@tibco.com] Sent: Wednesday, September 21, 2016 10:48 AM To: Crombie, Burnette N <bcrom...@utk.edu> Cc: r-help@r-project.org Subject: Re: [R] if/else help If you write your code as functions you can avoid the nasty 'if(exists("x"))x<-...' business this by writing default values for arguments to your function. They will be computed only when they are used. E.g., analyzeData <- function(a=0, b=0, c=0, d="x", r4 = data.frame(a, b, c, d)) { summary(r4) } > analyzeData(c=101:102) a b c d Min. :0 Min. :0 Min. :101.0 x:2 1st Qu.:0 1st Qu.:0 1st Qu.:101.2 Median :0 Median :0 Median :101.5 Mean :0 Mean :0 Mean :101.5 3rd Qu.:0 3rd Qu.:0 3rd Qu.:101.8 Max. :0 Max. :0 Max. :102.0 > analyzeData(r4=data.frame(a=10:11,b=20:21,c=30:31,d=c("x","y"))) a b c d Min. :10.00 Min. :20.00 Min. :30.00 x:1 1st Qu.:10.25 1st Qu.:20.25 1st Qu.:30.25 y:1 Median :10.50 Median :20.50 Median :30.50 Mean :10.50 Mean :20.50 Mean :30.50 3rd Qu.:10.75 3rd Qu.:20.75 3rd Qu.:30.75 Max. :11.00 Max. :21.00 Max. :31.00 Bill Dunlap TIBCO Software wdunlap tibco.com<http://tibco.com> On Tue, Sep 20, 2016 at 12:31 PM, Crombie, Burnette N <bcrom...@utk.edu<mailto:bcrom...@utk.edu>> wrote: If a data.frame (r4) does not exist in my R environment, I would like to create it before I move on to the next step in my script. How do I make that happen? Here is what I want to do from a code perspective: if (exists(r4)) { is.data.frame(get(r4)) } else { a <- 0, b <- 0, c <- 0, d <- "x", r4 <- data.frame(cbind(a,b,c,d)) } Thanks for your help, B [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org<mailto: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. [[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.