[Rcpp-devel] Passing large data frame

[Dirk Eddelbuettel]

Robert,

On 14 June 2010 at 12:36, Romain Francois wrote:
| Le 14/06/10 05:38, R_help Help a écrit :
| [...]
| > Secondly, I'm wondering why the POSIXct column in my data frame
| > appears as double when I pass a data frame as an argument into a
| > function or when I read it out from global environment map? Is there
| > anyway to ensure it appears as RcppDatetime? Thank you.
| >
| > Robert
| 
| Someone else will pick this up.

a) POSIXct really is a double and nothing more, so you could re-create a 
   RcppDatetimeVector from the double vector -- no information lossage

b) RcppFrame is a data structure for _creating data frame in C++ for return_
   rather than for retrieving a data frame from R

c) As Romain said, you are better off with Rcpp::DataFrame anyway

d) But that class (and the new API in general) do not have a datetime class
   yet so see point a) 

I have been mulling over what to do about a simple datetime time class. So
far, I haven't needed one (comparison between doubles work fine) so I had no
real motivation. Eventually we should have one.  For now you can just use
doubles and/or the old class.
   
-- 
  Regards, Dirk