Message-ID: <CAJJHHA9DHNKfgk8dghzbMsjrhH5JiVzZ80OPTabR592YooGntQ@mail.gmail.com>
Date: 2013-03-31T13:44:07Z
From: stat quant
Subject: [Rcpp-devel] DataFrame and passing by reference
Hello list,
looking at Rcpp::DataFrame in the
gallery<http://gallery.rcpp.org/tags/dataframe/>I realized that I
didn't know how to modify a DataFrame by reference.
Googling a bit I found this post on
SO<http://stackoverflow.com/questions/13773529/passing-a-data-table-to-c-functions-using-rcpp-and-or-rcpparmadillo>and
this post
on the archive<http://www.mail-archive.com/rcpp-devel at lists.r-forge.r-project.org/msg04919.html>
.
There is nothing obvious so I suspect I miss something big like "It is
already the case because" or "it does not make sense because".
I tried the following which compiled but the data.frame object passed to
updateDFByRef in R stayed untouched
#include <Rcpp.h>
using namespace Rcpp;
// [[Rcpp::export]]
void updateDFByRef(DataFrame& df) {
int N = df.nrows();
NumericVector newCol(N,1.);
df["newCol"] = newCol;
return;
}
Could somebody explain me what I am missing or kindly point me to a
document where I can find the explanation ?
Cheers
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