[Rcpp-devel] Convertion from SEXP to std::vector<unsigned>

Hi,

Rcpp::IntegerVector can not be converted to std::vector<unsigned>. Is
there a class that can help convert SEXP to std::vector<unsigned>?

The current walkaround can be something like the following. I'm
wondering if there is a better solution?

Rcpp::IntegerVector vec(vx);

std::vector<unsigned> v;

You should at least specify the size there so that push_back doesn't
need to allocate/reallocate and possibly overallocate.

std::vector<unsigned> v(vec.size());

You may be able to allocate from iterators as in

std::vector<unsigned> v(vec.begin(), vec.end());

but I'm not sure if that will do the automatic conversion from signed
int to unsigned.  Look up the different forms of constructors for
std::vector and the STL algorithms such as std::transform.

for (int i=0; i<vec.size(); i++) {
v.push_back(vec[i]);
}

--
Regards,
Peng

_______________________________________________
Rcpp-devel mailing list
Rcpp-devel at lists.r-forge.r-project.org
https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel