Dear Prof. Ripley Thank you for your reply and for changing the function in R-devel. I've intended to ask my question in way 2) but I probably have chosen a ambiguous formulation. :-)
Regards Christoph Buser -------------------------------------------------------------- Christoph Buser <[EMAIL PROTECTED]> Seminar fuer Statistik, LEO C13 ETH (Federal Inst. Technology) 8092 Zurich SWITZERLAND phone: x-41-44-632-4673 fax: 632-1228 http://stat.ethz.ch/~buser/ -------------------------------------------------------------- Prof Brian Ripley writes: > On Fri, 18 Nov 2005, Christoph Buser wrote: > > > Dear R core team > > and R-devel-listers. > > > Using the following code produces an empty plot (similar > > to col = NA): > > > >> plot(1:9, col = factor(rep(1:3,3), labels = c("red", "blue", "black"))) > > > > > > My question: Shouldn't one get at least a warning (or an error) > > if one tries to use a factor as col argument? > > > > Thanks for an answer. > > I can read that two ways > > 1) No, it should not give a warning, as it is programmed to take all > invalid values as 0. > > 2) Is the way it is programmed sensible (yes) or desirable (no)? > > The actual code is > > /* Convert a sexp element to an R color desc */ > /* We Assume that Checks Have Been Done */ > > unsigned int RGBpar(SEXP x, int i) > { > int indx; > if(isString(x)) { > return str2col(CHAR(STRING_ELT(x, i))); > } > else if(isInteger(x) || isLogical(x)) { > if(INTEGER(x)[i] == NA_INTEGER) > /* > * Paul 01/07/04 > * Used to be set to NA_INTEGER (see comment in name2col). > */ > return R_TRANWHITE; > indx = INTEGER(x)[i] - 1; > if(indx < 0) return Rf_dpptr(CurrentDevice())->bg; > else return R_ColorTable[indx % R_ColorTableSize]; > } > else if(isReal(x)) { > if(!R_FINITE(REAL(x)[i])) > /* > * Paul 01/07/04 > * Used to be set to NA_INTEGER (see comment in name2col). > */ > return R_TRANWHITE; > indx = REAL(x)[i] - 1; > if(indx < 0) return Rf_dpptr(CurrentDevice())->bg; > else return R_ColorTable[indx % R_ColorTableSize]; > } > return 0; /* should not occur */ > } > > but I could see no checks of type in any of the calling functions. Adding > a warning would be a good idea. > > > -- > 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
