A slightly improved version:
library(Rcpp)
code = '
SEXP test(List a)
{
auto l = Rf_length(a[0]);
using svec = std::vector<SEXP>;
std::vector<svec> x(l);
for (List b : a)
{
if (b.size() != l)
stop("Ragged input");
for (int i = 0; i != l; ++i)
x[i].push_back(b[i]);
}
return wrap(x);
}'
f = cppFunction(code = code, plugins = "cpp11")
res = lapply(f(list(list(T, 1, 'a'),
list(F, 2, 'b'))),
unlist)
On Sun, May 3, 2015 at 11:57 AM, Tim Keitt <tke...@utexas.edu> wrote:
> Here's a really bare-bones version. Not very pretty or complete, but it
> does do the job. Could the 'unlist' part be converted to Rcpp?
>
> THK
>
> library(Rcpp)
>
> code = '
> SEXP test(List a)
> {
> int l = Rf_length(a[0]);
> typedef std::vector<SEXP> svec;
> std::vector<svec> x(l);
> for (int i = 0; i != l; ++i)
> for (int j = 0; j != a.size(); ++j)
> {
> List b = a[j];
> x[i].push_back(b[i]);
> }
> return wrap(x);
> }'
>
> f = cppFunction(code = code)
>
> res = lapply(f(list(list(1, 'a'), list(2, 'b'))), unlist)
>
>
> On Sat, May 2, 2015 at 1:18 PM, Dirk Eddelbuettel <e...@debian.org> wrote:
>
>>
>> On 2 May 2015 at 10:49, William Dunlap wrote:
>> | Since translation from R to Rcpp is "seamless" I will leave that to you.
>>
>> One problem is with the strongly typed nature of C++. Rearranging
>> dynamicly
>> growing objects can be done. I think I used Boost's variant type a few
>> years. I am sure there are other possibilities. We should collect a few
>> and
>> compare. But in C++ please :)
>>
>> Dirk
>>
>> --
>> http://dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org
>>
>
>
>
> --
> http://www.keittlab.org/
>
--
http://www.keittlab.org/
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