[R] dumping/loading objects with 'tsp' attribute

[Gabor Grothendieck]

On 11/23/06, Antonio, Fabio Di Narzo <antonio.fabio at gmail.com> wrote:
> 2006/11/23, Prof Brian Ripley <ripley at stats.ox.ac.uk>:
> > On Thu, 23 Nov 2006, Antonio, Fabio Di Narzo wrote:
> >
> > > Dear all,
> > > I'm indirectly faced with the fact that setting the 'tsp' attribute of
> > > an object modifies its class definition:
> > >> class( structure(1:2, tsp=c(1,2,1), class=c("myts","ts")) )
> > > [1] "ts"   "myts"
> > >
> > > In general, this is of really little (ok, I admit: totally no)
> > > interest for me because 'myts' class is added just after assigning the
> > > 'tsp' attribute (by calling ts).
> > > However, this behaviour gives me troubles when re-loading a previously
> > > deparsed object, so that:
> > >> x <- ts(1:2)
> > >> class(x) <- c("myts", class(x))
> > >> dput( x , "temp.dat")
> > >> class(dget("temp.dat"))
> > > [1] "ts"   "myts"
> > >> unlink("temp.dat")
> > >
> > > In other words, my real problem should be restated as: how to safely
> > > dump (and then load) an object which has a (perhaps valid) "tsp"
> > > attribute?
> > > More generally: can someone suggest me a safer way to dump/restoring R objects?
> >
> > save/load.
>
> Ok. That seems to be the final statement: to be sure about the result,
> I have to use binary files for storing R objects (even pure data
> objects with attached attributes) instead of dumped R code.

If its mainly ascii you are after but the source file part is not important
then note that save can save to ascii files:

y <- x
save("x", file = "temp.rda", ascii = TRUE)
rm(x)
load("temp.rda")
identical(x, y)
readLines("temp.rda")
unlink("temp.rda")



> I will accept that (infact, as I can read in 'save' help page, those
> binaries should be portable across R platforms) and avoid boring you
> anymore :-)
>
> >
> > ?dput comes with copious warnings about the problems of doing what you are
> > attempting, so I wonder why you are surprised.
>
> I've seen. That's because I've asked for suggestions, and not called
> this a 'bug' or a 'nonsense' behaviour.
>
> >
> > --
> > Brian D. Ripley,                  ripley at stats.ox.ac.uk
> > Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> > University of Oxford,             Tel:  +44 1865 272861 (self)
> > 1 South Parks Road,                     +44 1865 272866 (PA)
> > Oxford OX1 3TG, UK                Fax:  +44 1865 272595
> >
>
>
> --
> Antonio, Fabio Di Narzo
> Ph.D. student at
> Department of Statistical Sciences
> University of Bologna, Italy
>
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