On Thu, 7 Jun 2007, Prof Brian Ripley wrote: > 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.)
I should have added 'The same for asInteger in R-devel'. I forgot to check R 2.5.0 (and suspect others did the same). > 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
