RcppExamples (version 0.1.10)

RcppDateExample: C++ classes for interfacing date and datetime R objects

Description

Rcpp has the classes Rcpp::Date, Rcpp::Datetime, Rcpp::DateVector and Rcpp::DatetimeVector.

Author

Dominick Samperi wrote the initial versions of Rcpp (and RcppTemplate) during 2005 and 2006. Dirk Eddelbuettel made some additions, and became maintainer in 2008. Dirk Eddelbuettel and Romain Francois have been extending Rcpp since 2009.

Details

In the C++ code for the RcppDateExample.cpp file:

        // [[Rcpp::export]]
        List DateExample(DateVector & dv, DatetimeVector & dtv) {
            Function formatDate("format.Date");
            Function formatDatetime("format.POSIXct");
            
            Rprintf("\nIn C++, seeing the following date value\n");
            for (int i=0; i<dv.size(); i++) {
                Rcout << as<std::string>(formatDate(wrap(dv[i]))) << std::endl;
                dv[i] = dv[i] + 7;		// shift a week
            }
            Rprintf("\nIn C++, seeing the following datetime value\n");
            for (int i=0; i<dtv.size(); i++) {
                Rcout << as<std::string>(formatDatetime(wrap(dtv[i]))) << std::endl;
                dtv[i] = dtv[i] + 0.250;    // shift 250 millisec
            }
            
           // Build result set to be returned as a list to R.
           return List::create(Named("date",   dv),
                               Named("datetime", dtv));
        }
    
    

References

Writing R Extensions, available at https://www.r-project.org.

Examples

# set up date and datetime vectors
dvec <- Sys.Date() + -2:2
dtvec <- Sys.time() + (-2:2)*0.5

# call the underlying  C++ function
result <- RcppDateExample(dvec, dtvec)

# inspect returned object
result