[R] Creating NA equivalent

[Jim Lemon]

Please pardon a comment that may be off-target as well as off-topic.
This appears similar to a number of things like fuzzy logic, where an
instance can take incompatible truth values.

It is known that an instance may have an attribute with a numeric
value, but that value cannot be determined.

It seems to me that an appropriate designation for the value is Unk,
perhaps with an associated probability of determination to distinguish
it from NA (it is definitely not known).

Jim

On Wed, Dec 22, 2021 at 6:55 AM Avi Gross via R-help
<r-help using r-project.org> wrote:
>
> I wonder if the package Adrian Dușa created might be helpful or point you along the way.
>
> It was eventually named "declared"
>
> https://cran.r-project.org/web/packages/declared/index.html
>
> With a vignette here:
>
> https://cran.r-project.org/web/packages/declared/vignettes/declared.pdf
>
> I do not know if it would easily satisfy your needs but it may be a step along the way. A package called Haven was part of the motivation and Adrian wanted a way to import data from external sources that had more than one category of NA that sounds a bit like what you want. His functions should allow the creation of such data within R, as well. I am including him in this email if you want to contact him or he has something to say.
>
>
> -----Original Message-----
> From: R-help <r-help-bounces using r-project.org> On Behalf Of Duncan Murdoch
> Sent: Tuesday, December 21, 2021 5:26 AM
> To: Marc Girondot <marc_grt using yahoo.fr>; r-help using r-project.org
> Subject: Re: [R] Creating NA equivalent
>
> On 20/12/2021 11:41 p.m., Marc Girondot via R-help wrote:
> > Dear members,
> >
> > I work about dosage and some values are bellow the detection limit. I
> > would like create new "numbers" like LDL (to represent lower than
> > detection limit) and UDL (upper the detection limit) that behave like
> > NA, with the possibility to test them using for example is.LDL() or
> > is.UDL().
> >
> > Note that NA is not the same than LDL or UDL: NA represent missing data.
> > Here the data is available as LDL or UDL.
> >
> > NA is built in R language very deep... any option to create new
> > version of NA-equivalent ?
> >
>
> There was a discussion of this back in May.  Here's a link to one approach that I suggested:
>
>    https://stat.ethz.ch/pipermail/r-devel/2021-May/080776.html
>
> Read the followup messages, I made at least one suggested improvement.
> I don't know if anyone has packaged this, but there's a later version of the code here:
>
>    https://stackoverflow.com/a/69179441/2554330
>
> Duncan Murdoch
>
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