[Rd] How to build a list with missing values? What is missing, anyway?

Peter Meilstrup peter.meilstrup at gmail.com
Fri Oct 5 03:31:26 CEST 2012

On Thu, Oct 4, 2012 at 6:12 PM, Bert Gunter <gunter.berton at gene.com> wrote:
> The R Language definition manual explains all of this. Read it.

I always reread that before I post to this list.

The only relevant mention of "missing" in the R Language Definition
that I could find were in section 4.1.2 on page 25, and that section
did not answer anything about "missing" as a special symbol (e.g. that
my be put in a formal argument list.)

There is another mention of `...` in section 4.3.2 and it does not
explain some things, such as under what circumstances one would get a
"`...` used in incorrect context" error.


>> Thanks.
>> Just so I have my mental model correct, I'm gathering that missing/``
>> is a symbol that the interpreter has a special rule for -- evaluating
>> it raises an error, as opposed to objects that evaluate to themselves
>> or variable names that evaluate to objects.
>> Does the same sort of thing explain the behavior of `...`? When the
>> interpreter comes across `...` in the arguments during evaluation of a
>> call, it trips a special argument-interpolating behavior?
>> Peter
>> ______________________________________________
>> R-devel at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
> --
> Bert Gunter
> Genentech Nonclinical Biostatistics
> Internal Contact Info:
> Phone: 467-7374
> Website:
> http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm

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