将StringVector与Rcpp连接 [英] Concatenate StringVector with Rcpp

问题描述

我不知道如何用Rcpp连接2个字符串。

I can not figure out how to concatenate 2 strings with Rcpp; and the documentation did not help me while I suspect there is an obvious answer.

http://gallery.rcpp.org/articles/working-with-Rcpp-StringVector/

http://gallery.rcpp.org/articles/strings_with_rcpp/

StringVector concatenate(StringVector a, StringVector b)
{
 StringVector c;
 c= ??;
 return c;
}

我期望此输出：

a=c("a","b"); b=c("c","d");
concatenate(a,b)
[1] "ac" "bd"

推荐答案

一种有效的解决方案是使用：

A working solution is to use :

#include <Rcpp.h>
using namespace Rcpp;

// [[Rcpp::export]]
CharacterVector concatenate(std::string x, std::string y)
{
               return wrap(x + y);
}

然后：

Vconcatenate=Vectorize(concatenate)
Vconcatenate(letters[1:2],letters[3:4])

或：

// [[Rcpp::export]]
CharacterVector concatenate(std::vector<std::string> x,std::vector<std::string> y)
{
  std::vector<std::string> res(x.size());
  for (int i=0; i < x.size(); i++)
  {
    res[i]=x[i]+y[i];
  }
  return wrap(res);
}

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