On Mon, Aug 6, 2012 at 5:27 PM, R. Michael Weylandt <michael.weyla...@gmail.com> wrote: > On Mon, Aug 6, 2012 at 9:53 AM, Liviu Andronic <landronim...@gmail.com> wrote: >> On Mon, Aug 6, 2012 at 4:48 PM, Liviu Andronic <landronim...@gmail.com> >> wrote: >>> string, something that I find strange. At best NA is the equivalent of >>> an empty string. > > Certainly not to my mind, unless you think that zero and NA should be > the same for integers and doubles as well. NA (in whatever form) is, > to my mind, _unknown_ which is very different than knowing 0. > This is a tricky question and I don't have a strong opinion yet.
> I'm not sure why that's the case, but it's documented on the help page > (under value): > > For ‘nchar’, an integer vector giving the sizes of each element, > currently always ‘2’ for missing values (for ‘NA’). > I most certainly missed this bit in the help page. > My guess is that it's this way for back-compatability from a time when > there probably wasn't a proper NA_character_ (that's the parser > literal for a character NA) and they really were just "NA" (the > string) -- perhaps in some far distant R 3.0 we'll see > nchar(NA_character_) = NA_integer_ > As David has also suggested (and Bert alluded), it may be worth having a nchar(..., returnNA=FALSE) argument, which if TRUE would return NA when it encounters NA values in the original vector. Thank you all for the comments. Regards Liviu ______________________________________________ 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.
