On Thu, 7 Jun 2007, Douglas Bates wrote: > On 6/6/07, Aniko Szabo <[EMAIL PROTECTED]> wrote: >> Thanks to everybody who responded to my question. >> asInteger(coerceVector(x,INTSXP)) indeed does what I need. I guess there >> is a lot I don't understand about type coercion, as I would not have >> expected it to work. > > It is better to use > > asInteger(x) > > which will do the coercion if necessary. When you do the coercion > yourself you should PROTECT the result then UNPROTECT it. Calling > asInteger directly avoids this overhead without the risk of losing > data in a garbage collection. asInteger can accomplish this because > only the first element of the SEXP x is converted to an integer.
I have to say I am puzzled. IntegerFromString works on a CHARSXP, and furthermore does not check its argument (which is one reason why it is no longer even exposed). AFAICS, coerceVector(x,INTSXP) will not accept a CHARSXP, but it will accept a STRSXP. (The same for asInteger.) So two ways to do this for vector 'x' are asInteger(x) INTEGER(coerceVector(x,INTSXP))[0] provided in the second case you know 'x' has length at least 1. But the first is both safer and more efficient. If you really have a CHARSXP, then you are not really supposed to work with 'bare' CHARSXPs unless you know what you are doing (in which case you don't need to ask ...). > >> >> Aniko >> >> -----Original Message----- >> From: Seth Falcon [mailto:[EMAIL PROTECTED] >> Sent: Tuesday, June 05, 2007 11:24 PM >> To: Aniko Szabo >> Cc: r-devel@r-project.org >> Subject: Re: [Rd] missing IntegerFromString() >> >> Hi Aniko, >> >> "Aniko Szabo" <[EMAIL PROTECTED]> writes: >> >>> I have created a DLL not so long ago using C code. My code used the >>> IntegerFromString() function that used to be exported in the >>> Rinternals.h header file (and thus easily accessible). Recently I >>> upgraded to R 2.5.0 and my DLL stopped working. I see that the >>> IntegerFromString() function is not exported in any of the header >> files >>> in the RHOME\include directory. Is it possible for me to use it >> without >>> installing all R source files? I can see that the function is in >>> coerce.c, however it #includes other stuff that I don't have and I am >>> afraid to mess things about by doing things I don't understand. Or >>> perhaps there is another function that is intended to be used >>> instead? >> >> I think you want asInteger (which calls IntegerFromString). This is >> in RHOME/include/Rinternals.h >> >> Best Wishes, >> >> + seth >> >> PS: Nice to see you again :-) >> >> >> -- >> Seth Falcon | Computational Biology | Fred Hutchinson Cancer Research >> Center >> http://bioconductor.org >> >> ______________________________________________ >> R-devel@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-devel >> > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
