issue with nzchar() ?
On Mon, Aug 6, 2012 at 5:27 PM, R. Michael Weylandt
<michael.weylandt at gmail.com> wrote:
On Mon, Aug 6, 2012 at 9:53 AM, Liviu Andronic <landronimirc at gmail.com> wrote:
On Mon, Aug 6, 2012 at 4:48 PM, Liviu Andronic <landronimirc at 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