I am sorry for that, i understand you. I think i should read your book seamless R and C++ ... first. I shoudn't just want to get a quick guide which maybe convinient to me but the oppsite to you . BTW, i am a student from SJTU in china,and Google can't be used in china now. I registed " [email protected]" in NetEase mailbox, then i use it to join the maillist. I used r-help maillist just several days ago. There must be a lot of things i don't know to use maillist like filter rule and the problem you said. but i will figure them out .
At 2014-08-05 08:50:02, "Dirk Eddelbuettel" <[email protected]> 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" <[email protected]> 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 <[email protected]> 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? >| >| >| >| >| _______________________________________________ >| Rcpp-devel mailing list >| [email protected] >| >https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel >| >| >| >| >| >| _______________________________________________ >| Rcpp-devel mailing list >| [email protected] >| https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel > >-- >http://dirk.eddelbuettel.com | @eddelbuettel | [email protected]
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