[Rd] 1954 from NA

[Nicholas Tierney]

Hi all,

When first hearing about ALTREP I've wondered how it might be able to be
used to store special missing value information - how can we learn more
about implementing ALTREP classes? The idea of carrying around a "meaning
of my NAs" vector, as Gabe said, would be very interesting!

I've done a bit on creating "special missing values", as done in SPSS, SAS,
and STATA, here:
http://naniar.njtierney.com/articles/special-missing-values.html  (Note
this approach requires carrying a duplicated dataframe of missing data
around with the data - which I argue makes it easier to reason with, at the
cost of storage. However this is just my approach, and there are others out
there).

Best,

Nick

On Tue, 25 May 2021 at 01:16, Adrian Dușa <dusa.adrian using gmail.com> wrote:

> On Mon, May 24, 2021 at 5:47 PM Gabriel Becker <gabembecker using gmail.com>
> wrote:
>
> > Hi Adrian,
> >
> > I had the same thought as Luke. It is possible that you can develop an
> > ALTREP that carries around the tagging information you're looking for in
> a
> > way that is more persistent (in some cases) than R-level attributes and
> > more hidden than additional user-visible columns.
> >
> > The downsides to this, of course, is that you'll in some sense be doing
> > the same "extra vector for each vector you want tagged NA-s within" under
> > the hood, and that only custom machinery you write will recognize things
> as
> > something other than bog-standard NAs/NaNs.  You'll also have some
> problems
> > with the fact that data in ALTREPs isn't currently modifiable without
> > losing ALTREPness. That said, ALTREPs are allowed to carry around
> arbitrary
> > persistent information with them, so from that perspective making an
> ALTREP
> > that carries around a "meaning of my NAs" vector of tags in its metadata
> > would be pretty straightforward.
> >
>
> Oh... now that is extremely interesting.
> It is the first time I came across the ALTREP concept, so I need to study
> the way it works before saying anything, but definitely something to
> consider.
>
> Thanks so much for the pointer,
> Adrian
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-devel using r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>

	[[alternative HTML version deleted]]