Not the most beautiful solution: start your message with carriage return, e.g.
> stop("\rA long enough message"); A long enough message > stop("\rfoo"); fooor: /H On Mon, Sep 14, 2009 at 5:06 PM, Bert Gunter <gunter.ber...@gene.com> wrote: > I don't believe the solution proposed below works and anyway misses the > whole point of tryCatch(), which is **not** to test manually: > > f <- function(i){ > val <- tryCatch(get("i"), error = function(e)"input error") > val ## can test val and carry on if not an error > } > > ## testit > >> f() > [1] "input error" >> f(2) > [1] 2 >> > > Bert Gunter > Genentech Nonclinical Biostatistics > > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf Of Henrique Dallazuanna > Sent: Monday, September 14, 2009 12:44 PM > To: carol white > Cc: r-h...@stat.math.ethz.ch > Subject: Re: [R] how to determine if a variable is already set? > > Try this: > > if (!exists("i")) > tryCatch(stop(""), > error = function(e)invisible(), > finally=print("Please set the i variable")) > > On Mon, Sep 14, 2009 at 3:38 PM, carol white <wht_...@yahoo.com> wrote: > >> Thanks to your replies. >> >> In fact, the problem doesn't come from "exists" but from "stop" that >> displays Error even if call. = FALSE. To answer to Dan, I quoted the >> pramater of exists. So when the variable is not defined, stop displays the >> expression message preceded by "Error". So the question was how not to >> display "Error" or if there is another function that does stop's job > without >> displaying "Error"? >> >> Cheers, >> >> --- On Sun, 9/13/09, Michael Knudsen <micknud...@gmail.com> wrote: >> >> From: Michael Knudsen <micknud...@gmail.com> >> Subject: Re: [R] how to determine if a variable is already set? >> To: "carol white" <wht_...@yahoo.com> >> Cc: r-h...@stat.math.ethz.ch >> Date: Sunday, September 13, 2009, 7:06 AM >> >> On Fri, Sep 11, 2009 at 7:15 PM, carol white <wht_...@yahoo.com> wrote: >> >> > It might be a primitive question but how it is possible to determine if > a >> variable is initialized in an environment? >> >> What about this? >> >> > "x" %in% ls() >> [1] FALSE >> > x = 41 >> > "x" %in% ls() >> [1] TRUE >> >> Best, >> Michael >> >> -- >> Michael Knudsen >> micknud...@gmail.com >> http://lifeofknudsen.blogspot.com/ >> >> >> >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> 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. >> > > > > -- > Henrique Dallazuanna > Curitiba-Parana-Brasil > 250 25' 40" S 490 16' 22" O > > [[alternative HTML version deleted]] > > ______________________________________________ > 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.