2012/1/4 Romain François <rom...@r-enthusiasts.com>: > Le 04/01/12 14:29, Hadley Wickham a écrit : > >> Hi all, >> >> I'm still just getting my feet wet in Rcpp, so please excuse the >> naivety of my question, but is this the appropriate idiom for treating >> an input as a C++ scalar? >> >> f<- cxxfunction(signature(x = "integer"), plugin = "Rcpp", ' >> Rcpp::IntegerVector x1(x); >> int x2 = x1[0]; >> >> return(Rcpp::NumericVector(x2)); >> ') >> >> i.e. is there any way I can turn x in x2 more succinctly? (This >> function is just for illustrative purposes - I'm trying to do >> something at least a little more complicated) >> >> Thanks! >> >> Hadley > > Yep, > > We have "as" for this, and wrap for the other way around: > > > f<- cxxfunction(signature(x = "integer"), plugin = "Rcpp", ' > int x2 = as<int>(x) ; > > return wrap(x2) ; > ')
As I mentioned in another thread, I prefer the idiom int n2 = ::Rf_asInteger(n); because asInteger is part of the R API (in Rcpp it must be called as Rf_asInteger - the :: is a hint to the compiler that it will be found in the global namespace). Functions like asInteger and asReal are used in thousands of places in the base R code and have been optimized to death as well as being as general as they can possibly be. _______________________________________________ Rcpp-devel mailing list Rcpp-devel@lists.r-forge.r-project.org https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
