R devel - Jun 2014 - using 2D array of SEXP for creating dataframe

Hi ,

For our production package i need to create a dataframein C . So I wrote
the following code

SEXP dfm ,head,df , dfint , dfStr,lsnm;

*SEXP  valueVector[2];*

char *ab[3] = {"aa","vv","gy"};
int sn[3] ={99,89,12};
char *listnames[2] = {"int","string"};
int i,j;

//============================
PROTECT(df = allocVector(VECSXP,2));

*PROTECT(valueVector[0] = allocVector(REALSXP,3));*
*PROTECT(valueVector[1] = allocVector(VECSXP,3));*


PROTECT(lsnm = allocVector(STRSXP,2));

SET_STRING_ELT(lsnm,0,mkChar("int"));
SET_STRING_ELT(lsnm,1,mkChar("string"));
SEXP rawvec,headr;
unsigned char str[24]="abcdef";

for ( i = 0 ; i < 3; i++ ) {

*SET_STRING_ELT(valueVector[1],i,mkChar(ab[i]));*
*REAL(valueVector[0])[i] = sn[i];*
}


It works , data frame is being created and executed properly .
Just curious , if I am doing anything wrong or is there another way around
for creation of data-frame .  I am concerned about the SEXP 2D array .

Thanks,
Sandip

	[[alternative HTML version deleted]]

Hi,

On 06/26/2014 02:32 PM, Sandip Nandi wrote:
> Hi ,
>
> For our production package i need to create a dataframein C . So I wrote
> the following code
>
> SEXP dfm ,head,df , dfint , dfStr,lsnm;
>
> *SEXP  valueVector[2];*
>
> char *ab[3] = {"aa","vv","gy"};
> int sn[3] ={99,89,12};
> char *listnames[2] = {"int","string"};
> int i,j;
>
> //============================>
> PROTECT(df = allocVector(VECSXP,2));
>
> *PROTECT(valueVector[0] = allocVector(REALSXP,3));*
> *PROTECT(valueVector[1] = allocVector(VECSXP,3));*
>
>
> PROTECT(lsnm = allocVector(STRSXP,2));
>
> SET_STRING_ELT(lsnm,0,mkChar("int"));
> SET_STRING_ELT(lsnm,1,mkChar("string"));
> SEXP rawvec,headr;
> unsigned char str[24]="abcdef";
>
> for ( i = 0 ; i < 3; i++ ) {
>
> *SET_STRING_ELT(valueVector[1],i,mkChar(ab[i]));*
> *REAL(valueVector[0])[i] = sn[i];*
> }
>
>
> It works , data frame is being created and executed properly .
Really? You mean, you can compile this code right? Otherwise it's
incomplete: you allocate but do nothing with 'df'. Same with
'lsnm'.
And you don't UNPROTECT. With no further treatment, 'df' will be an
unnamed list containing junk data, but not the data.frame you expect.
So there are a few gaps that would need to be filled before this code
actually works as intended.

Maybe try and come back again with specific questions?

Cheers,
H.
  > Just curious , if I am doing anything wrong or is there another way 
around
> for creation of data-frame .  I am concerned about the SEXP 2D array .
>
> Thanks,
> Sandip
>
> 	[[alternative HTML version deleted]]
>
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> https://stat.ethz.ch/mailman/listinfo/r-devel
>
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