[R] Creating NA equivalent

Avi Gross @v|gro@@ @end|ng |rom ver|zon@net
Tue Dec 21 20:45:44 CET 2021

I wonder if the package Adrian Dușa created might be helpful or point you along the way.

It was eventually named "declared" 


With a vignette here:


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:


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:


Duncan Murdoch

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