Don MacQueen
Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062
On 11/9/14, 10:07 AM, "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.