Add assignment operator to DimNameProxy

[fplaza]

#include <Rcpp.h>
using namespace Rcpp;

// [[Rcpp::export]]
NumericMatrix test_mat(const NumericMatrix& mat)
{
  const int num_rows = mat.rows();
  const int num_cols = mat.cols();
  NumericMatrix res_mat(num_rows, num_cols);
  rownames(res_mat)=rownames(mat);
  colnames(res_mat)=colnames(mat);

  return res_mat;
}




/*** R
mat=matrix(1:150,nrow=10,ncol=15,byrow=T)
rownames(mat)=sapply(1:10,as.character)
colnames(mat)=sapply(1:15,as.character)

mat_res=test_mat(mat)

rownames(mat_res)
colnames(mat_res)
*/

Before:

> mat=matrix(1:150,nrow=10,ncol=15,byrow=T)

> rownames(mat)=sapply(1:10,as.character)

> colnames(mat)=sapply(1:15,as.character)

> mat_res=test_mat(mat)

> rownames(mat_res)
NULL

> colnames(mat_res)
NULL

After:

> mat=matrix(1:150,nrow=10,ncol=15,byrow=T)

> rownames(mat)=sapply(1:10,as.character)

> colnames(mat)=sapply(1:15,as.character)

> mat_res=test_mat(mat)

> rownames(mat_res)
 [1] "1"  "2"  "3"  "4"  "5"  "6"  "7"  "8"  "9"  "10"

> colnames(mat_res)
 [1] "1"  "2"  "3"  "4"  "5"  "6"  "7"  "8"  "9"  "10" "11" "12" "13" "14" "15"

After:

[eddelbuettel]

This looks pretty straightforward -- in favour. Any seconds?

[kevinushey]

It looks like you already retrieved this above with SEXP dim = Rf_getAttrib(data_, R_DimSymbol) -- is this line superfluous?

EDIT: I see now the interface is mostly copied from the other operator=; I guess that's a similar oversight in the previous implementation.

[romainfrancois]

And while you're there, now that stop does the printf thing, the whole std::stringstream can be replaced.

[kevinushey]

This should probably have a NULL check (same with older implementation)

[kevinushey]

I agree this is a good change; it would probably be best to refactor the code into its own function (which both operator= methods can call) rather than duplicating code, however.

[fplaza]

I made the change you asked.
Tell me if it suits you.

[eddelbuettel]

Looks good to me.

[fplaza]

#include <Rcpp.h>
using namespace Rcpp;

// [[Rcpp::export]]
void test_mat()
{
  const int num_rows = 2;
  const int num_cols = 2;
  NumericMatrix m1(num_rows, num_cols);
  NumericMatrix m2(num_rows, num_cols);
  rownames(m1)=CharacterVector::create("a", "b");
  rownames(m1)=rownames(m2);
}




/*** R
test_mat()
*/

Result

`test_mat()
Error in eval(expr, envir, enclos) : 
  dimension extent is '2' while length of names is '0'

I think this code should not produce an error as it works in R. What do you think?

[kevinushey]

I agree that the code shouldn't produce an error; in fact, it looks like in current Rcpp we just get the wrong result:

#include <Rcpp.h>
using namespace Rcpp;

// [[Rcpp::export]]
NumericMatrix test_mat()
{
   const int num_rows = 2;
   const int num_cols = 2;
   NumericMatrix m1(num_rows, num_cols);
   NumericMatrix m2(num_rows, num_cols);
   rownames(m1)=CharacterVector::create("a", "b");
   rownames(m1)=rownames(m2);
   return m1;
}

/*** R
test_mat()
*/

gives

> Rcpp::sourceCpp('~/test.cpp')

> test_mat()
  [,1] [,2]
a    0    0
b    0    0

It looks to me like the second rownames assignment should have cleared the rownames of m1; if you are willing would you be able to tackle that as well?

Thanks for working on this!

[fplaza]

This does the trick

if (Rf_length(other) != 0 && INTEGER(dims)[dim_] != Rf_length(other))

but it looks a bit dirty.

[fplaza]

The last commit fixes the following cases:

#include <Rcpp.h>
using namespace Rcpp;


// [[Rcpp::export]]
NumericMatrix test_mat2()
{

  const int num_rows = 2;
  const int num_cols = 2;
  NumericMatrix m1(num_rows, num_cols);
  rownames(m1)=CharacterVector::create('a','b');
  rownames(m1)=CharacterVector::create();
  return m1;
}


// [[Rcpp::export]]
NumericMatrix  test_mat()
{
  const int num_rows = 2;
  const int num_cols = 2;
  NumericMatrix m1(num_rows, num_cols);
  NumericMatrix m2(num_rows, num_cols);
  rownames(m1)=CharacterVector::create("a", "b");
  rownames(m1)=rownames(m2);
  return m1;
}




/*** R
test_mat()
test_mat2()
*/

> test_mat()
     [,1] [,2]
[1,]    0    0
[2,]    0    0

> test_mat2()
     [,1] [,2]
[1,]    0    0
[2,]    0    0

It is ok to do so in R

> m1=matrix(nrow = 2,ncol = 2)
> rownames(m1)=c(1,2)
> rownames(m1)
[1] "1" "2"
> m2=matrix(nrow = 2,ncol = 2)
> rownames(m1)=rownames(m2)
> rownames(m1)
NULL
> rownames(m1)=c(1,2)
> rownames(m1)=c()
> rownames(m1)
NULL

[kevinushey]

We should check that dims is non-null here, e.g. if (dims != R_NilValue && ...)

[kevinushey]

Thanks! I have one more nitpick re: a null check and then I think it's ready for merge.

[fplaza]

I am not sure it can happen because a DimNameProxy object is currently created only from a Matrix.

[kevinushey]

Good point -- okay, then I think this is good to go. @eddelbuettel, any other comments?

[eddelbuettel]

Yup, let's fold this in.