Le 07/12/2019 à 00:29, Qiang Kou a écrit :
What about using "TYPEOF"? Please see R Internals
(https://cran.r-project.org/doc/manuals/r-release/R-ints.html#SEXPTYPEs)
for more details.
... and if you want to convert integer encoded SEXPTYPE to a human
readable string you can use
const char * Rf_type2char(SEXPTYPE);
By the way, conversion in the opposite direction is made by
SEXPTYPE Rf_str2type(const char *);
Best,
Sergueï.
#include <Rcpp.h>
using namespace Rcpp;
// [[Rcpp::export]]
DataFrame rcpp_df(){
NumericVector numeric = {1,3};
IntegerVector integer = {1,3};
CharacterVector character = {"B","D"};
LogicalVector logical = {false, true};
DataFrame df = DataFrame::create(Named("numeric") = numeric,
Named("integer") = integer,
Named("character") = character,
Named("logical") = logical);
Rcpp::Rcout << "numeric:" << TYPEOF(df["numeric"]) << std::endl;
Rcpp::Rcout << "integer:" << TYPEOF(df["integer"]) << std::endl;
Rcpp::Rcout << "character:" << TYPEOF(df["character"]) << std::endl;
Rcpp::Rcout << "logical:" << TYPEOF(df["logical"]) << std::endl;
return df;
}
/*
> Rcpp::sourceCpp("test.cc")
> df <- rcpp_df()
numeric:14
integer:13
character:13
logical:10
*/
On Fri, Dec 6, 2019 at 2:59 PM Brook Milligan <br...@nmsu.edu
<mailto:br...@nmsu.edu>> wrote:
Is there a way to discover the value type for the result of calling
DataFrame::operator[]? For example, is there a metafiction that
will deduce the type?
A similar question could be asked about the result of calling
Vector::operator[].
I understand that these functions actually return a proxy, but it
would be very helpful to find out the underlying value type.
Thanks for your help.
Cheers,
Brook
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