RcppDataFrame: Rcpp::DataFrame example for Rcpp

In RcppExamples: Examples using Rcpp to interface R and C++

Description

A DataFrame can be passed C++ and can be instantiated as a corresponding C++ object using the Rcpp API.

This example shows (in the corresponding C++ code) how to access, modify and create a data frame.

Details

Usage of Rcpp::DataFrame is fully defined in the respective header file.

The C++ source file corresponding to the this function does the following (inside of a try/catch block):

      // construct the data.frame object
      Rcpp::DataFrame DF(Dsexp);

      // and access each column by name
      Rcpp::IntegerVector a = DF["a"];
      Rcpp::CharacterVector b = DF["b"];
      Rcpp::DateVector c = DF["c"];
      
      // do something
      a[2] = 42;
      b[1] = "foo";
      c[0] = c[0] + 7;                      // move up a week

      // create a new data frame
      Rcpp::DataFrame NDF = 
	  Rcpp::DataFrame::create(Rcpp::Named("a")=a,
				  Rcpp::Named("b")=b,
				  Rcpp::Named("c")=c);

      // and return old and new in list
      return(Rcpp::List::create(Rcpp::Named("origDataFrame")=DF,
				Rcpp::Named("newDataFrame")=NDF));
  

Author(s)

Dirk Eddelbuettel and Romain Francois

Examples

  ## Not run: 
  RcppDataFrame()
  
## End(Not run)

Example output

Original data frame before call:
  a b          c
1 1 A 2011-01-01
2 2 B 2011-01-02
3 3 C 2011-01-03

After call, original and new data frames:
$origDataFrame
   a   b          c
1  1   A 2011-01-08
2  2 foo 2011-01-02
3 42   C 2011-01-03

$newDataFrame
   a   b          c
1  1   A 2011-01-08
2  2 foo 2011-01-02
3 42   C 2011-01-03

$origDataFrame
   a   b          c
1  1   A 2011-01-08
2  2 foo 2011-01-02
3 42   C 2011-01-03

$newDataFrame
   a   b          c
1  1   A 2011-01-08
2  2 foo 2011-01-02
3 42   C 2011-01-03

RcppExamples documentation built on May 2, 2019, 4:46 p.m.