[Rcpp-devel] NA value for dates

[Dirk Eddelbuettel]

On 5 October 2012 at 21:39, Theodore Lytras wrote:
| Hello all,
| 
| I am trying to pass from C++ to R a DateVector with a few missing items (NAs).
| I can't seem to find a way, though. 
| There does not seem to be a NA_DATE (like NA_REAL, etc), and the default 
| constructor for Rcpp::Date creates a date of "-5877641-06-23". 
| 
| I have even tried to pass an Rcpp::NumericVector and convert like this:
| 
| Rcpp::NumericVector a = Rcpp::NumericVector::create(3883, NA_REAL, 15120);
| Rcpp::Language call("as.Date", a, Rcpp::Named("origin", "1970-1-1"));
| Rcpp::DateVector b(3);
| aa = call.eval();
| 
| but I still get  "1980-08-19"    "-5877641-06-23"    "2011-05-26" .
| 
| The only way to get the expected output is by:
| 
| Rcpp::NumericVector a = Rcpp::NumericVector::create(3883, NA_REAL, 15120);
| R["a"] = a;
| R.parseEvalQ("aaa <- as.Date(a, origin=\"1970-1-1\")");
| 
| Isn't there any better way to specify a NA for dates, or check if an 
| Rcpp::Date is NA ??

I've never tried this, but as Dates in R really are just integers since the
epoch -- so maybe the NA_INTEGER aka R_NaInt will work?

At a more conceptual level, NA shouldn't really be in dates, right?  Either
is a valid date, or it is missing (NULL).  There simply is no such thing as
Feb 30 or April 31.

Dirk
 
| Thank you in advance,
| 
| Theodore Lytras
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-- 
Dirk Eddelbuettel | edd at debian.org | http://dirk.eddelbuettel.com