[Rd] How to build a list with missing values? What is missing, anyway?
gunter.berton at gene.com
Fri Oct 5 05:07:53 CEST 2012
On Thu, Oct 4, 2012 at 6:31 PM, Peter Meilstrup
<peter.meilstrup at gmail.com> wrote:
> 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
Page 15, "NA handling" seems "relevant, " as does ?NA (at the command
prompt in R).
See also 2.5 in the Introduction to R tutorial.
> 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
See section 2.1.9 of the Language Definition manual and 10.4 of Intro to R.
> explain some things, such as under what circumstances one would get a
> "`...` used in incorrect context" error.
How could it possibly know that?
>>> 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?
>>> R-devel at r-project.org mailing list
>> Bert Gunter
>> Genentech Nonclinical Biostatistics
>> Internal Contact Info:
>> Phone: 467-7374
Genentech Nonclinical Biostatistics
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