[Rcpp-devel] [Rcpp] How can i call a R function in Cpp source code?

[Sven E. Templer]

ii), e.g.:

http://www.mail-archive.com/search?q=call+R+function&l=rcpp-devel%40lists.r-forge.r-project.org

or try yourself:

http://www.mail-archive.com/rcpp-devel@lists.r-forge.r-project.org/

Nevertheless I liked the question and learned something today (thank
you Romain). So the trend is at least away from, and not towards iii).
And for iv), nice alias, though... it may also be political.

On 5 August 2014 14:50, Dirk Eddelbuettel <edd at debian.org> wrote:
>
> On 5 August 2014 at 17:30, super wrote:
> |
> | Yes , maybe that is very close to my needs , sorry for my pool english
> | expression. But, the following code can't work:
> | double meanC(NumericVector x) {
> |    Function mean=Environment("package::base")["mean"];
> |    return mean(x);
> | }
> | with the error "can't convert SEXP to double"
> | How can i fix it ? Tks.
>
> With all due respect:
>
>  i)    you have not motivated why you need mean from R
>
>  ii)   how to call an R function from Rcpp as been discussed on this list
>        probably half a dozen times by now, so please consider learning how to
>        search the list archive via Google
>
>  iii)  you are showing a somewhat larger amount of unfamiliarity with Rcpp
>
>  iv)   you are hiding behind an anon mail handle in violation of the common
>        R mailing list standards we follow here too
>
> so I am not going out of my way to repeat all of which you can already find
> via ii) another time for you.
>
> Dirk
>
>
> | At 2014-08-05 04:30:32, "Romain Francois" <romain at r-enthusiasts.com> wrote:
> |
> |     Not sure what you mean by hide the R function. You can extract a function
> |     by its name on the C++ side :
> |
> |     Function bazinga("mean") ;
> |
> |     or extract it from a particular environment, e.g.
> |
> |     Environment("package:base")["mean"]
> |
> |     or
> |
> |     Environment base("package:base") ;
> |     Function foo = base["mean"]
> |
> |     Romain
> |
> |     Le 5 août 2014 à 09:26, super <rcppmail at 163.com> a écrit :
> |
> |
> |         Hello Rcppusers,
> |           I want to call  a  r function in Cpp code, e.g.
> |          int  meanC( NumericVector x) {
> |             return mean(x,_["na.rm"]=TRUE);
> |         }
> |         Here function mean is a r function not rewrittened  Rcpp version's
> |         mean. I do know one way to do this:
> |          int  meanC( Function f,NumericVector x) {
> |             return f(x,_["na.rm"]=TRUE);
> |         }
> |         Then  meanC(mean,1:3)
> |         but can i hidden the true r function called ?  Is  r functions packed
> |         into some namespace?
> |
> |
> |
> |
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> |
> |
> |
> |
> |
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> --
> http://dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org
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