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

From: Bert Gunter <gunter.berton_at_gene.com>
Date: Thu, 04 Oct 2012 18:12:48 -0700

The R Language definition manual explains all of this. Read it.

On Thu, Oct 4, 2012 at 3:53 PM, Peter Meilstrup <peter.meilstrup_at_gmail.com> wrote:
> On Wed, Oct 3, 2012 at 11:21 PM, Josh O'Brien <joshmobrien@gmail.com> wrote:
>>
>>>Say I have argnames <- c("a", "b", "c").
>> >From that I want to construct the equivalent of alist(a=, b=, c=).
>>
>> Here's a one liner that'll do that for you:
>>
>> argnames <- letters[1:3]
>> setNames(rep(list(bquote()), length(argnames)), argnames)
>
> 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
>
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> R-devel_at_r-project.org mailing list
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-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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Received on Fri 05 Oct 2012 - 11:57:11 GMT

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