[R] Reading .rdata files

[Duncan Murdoch]

On 13-02-02 2:23 PM, Andrew DeCarlo wrote:
> Hello,
>
> I am a developer working on extracting information from .rdata files using
> java. I have been looking through the documentation a lot trying to figure
> out how to read these files, but am a bit stuck at the moment.
>
> I have generated two .RDATA files from StatTransfer and have noticed that
> they both begin in similar ways.
>
> *File 1*
>
> RDA2
> A
> 2
> 131585
> 66560
> 1026
> 1
> 4105
> 10
> .Traceback
> 254
> 1026
> 1
> 4105
> *8  <- these are the only difference*
> SPSSTest <-FileName
> 787
>
> *
> *
> *File 2*
>
> RDA2
> A
> 2
> 131585
> 66560
> 1026
> 1
> 4105
> 10
> .Traceback
> 254
> 1026
> 1
> 4105
> *9 **<- these are the only difference*
> statatest <-FileName
> 787
>
> Because of the remarkable similarity between these two beginning segments I
> assume that this is some sort of header. After examining the R Internals
> Manual (Section 1.8) I was able to discover that the first line describes
> the file RDA2 means its an ascii data file opposed to XDR or word order
> binary and the 2 indicates that it is version 2 of R. After this first line
> there are supposed to be 3 integers that also describe the version.
>
> However this is pretty much where section 1.8 ends and even though I
> searched through the rest of the document (and a lot of Google) I couldn't
> find anything about what the rest of the bytes/numbers indicate. I may just
> be missing something (I have seen a lot of people reference the Internals
> Manual) but is there any documentation on the different data files (RDA,
> RDX, RDB) and how they are organized.
>
> Any info would be greatly appreciated. Thanks a bunch!

You could try the source code:  the files are written by the code in

https://svn.r-project.org/R/trunk/src/main/serialize.c

The comments in there describe it, and the code does what it does.

Duncan Murdoch