[R] Is it possible to define another kind of NA

[Bert Gunter]

Ouch!

The values are **NOT** missing -- they are (left) censored, and need
to be handled by appropriate censored data methods. I suggest you
(all!) either read up on this or consult someone locally who has
knowledge of such methods.

-- Bert

Bert Gunter
Genentech Nonclinical Biostatistics
(650) 467-7374

"Data is not information. Information is not knowledge. And knowledge
is certainly not wisdom."
Clifford Stoll




On Sun, Nov 9, 2014 at 10:40 AM, Dustin Tran <dustinviettran at gmail.com> wrote:
> Hi Marc,
>
> This may be a helpful link: http://stackoverflow.com/questions/16074384/specify-different-types-of-missing-values-nas
>> On Nov 9, 2014, at 1:07 PM, Marc Girondot <marc_grt at yahoo.fr> wrote:
>>
>> Dear member list,
>>
>> In many experimental sciences, there is a lower detection limit (LDL) when a dosage of a product is done. Then some samples are evaluated to be below this limit.
>> I search for the best way to indicate in a data.frame that some values are such LDL. Ideally, an equivalent of NA would be the best.
>> Until now I manage by indicating all the column in characters.
>> So the question is: is it possible to define a value that could be named LDL and that could take place in vectors or data.frame such as:
>> v <- c(0.2, 0.28, LDL, 0.9) is the same way that NA can be used.
>> with of course a function is.ldl(v) that would return F F T F
>>
>> Thanks a lot for any direction to solve this
>>
>> Marc
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.