如何将Rcpp :: DateVector复制到std :: vector <boost::gregorian::date>

Question

I want to pass data from zoo object into my program in C++ using Rinside , but I don't know how to pass date.

Here is an example

 RInside R(argc, argv);              // create an embedded R instance


std::string cmd = "suppressMessages(library(zoo)); "
                  "z <- zoo(rnorm(10), as.Date('2000-01-01') - 0:10);"; 

R.parseEvalQ(cmd); 

 std::vector<double> v = Rcpp::as< std::vector< double > >(R.parseEval("coredata(z)"));
Rcpp::DateVector   d ( (SEXP) R.parseEval("index(z)") );

std::vector<boost::gregorian::date> dt =   //How assign d to dt ?

Answer 1

You need simple converters such as this in the RcppBDT package :

template <> boost::gregorian::date as( SEXP dtsexp ) {
    Rcpp::Date dt(dtsexp);
    return boost::gregorian::date(dt.getYear(), dt.getMonth(), dt.getDay());
}

which you then need to vectorise. Alternative, maybe use integer vector (with days since epoch).

Edit: An there is an entire Rcpp Gallery post devoting to this, as well as several more dealing in related topics.