[R] how to use "..."

Ivan Calandra ivan.calandra at u-bourgogne.fr
Mon Jan 21 11:32:45 CET 2013

Since this topic was mine originally, I supposed I can give my opinion, 
for what it's worth!

First, it is true that there is some help in the manuals. The problem 
with these manuals (or at least, my problem) is that there were much too 
complicated when I started to learn R. Then I got used to other ways of 
looking for help, especially ? or help(). Now that I understand more 
about R, I should think about the manuals again.
Because of this, if "..." should not be included in a help page, I 
believe that ?"..." should at least lead to the relevant documentation.

Now to the documentation itself. I find this "..." very strange; it is 
not intuitive at all for me. And the explanations in the manuals 
(Introduction to R and R language definition) are very short, without 
any details and real practical examples (please correct me if I missed 
something). This construct is very easy to use when it is implemented in 
some functions, but somehow I don't feel at ease when using it to write 
my own functions; I cannot predict how it should work, I can only try 
and see what happens. Actually I feel that it is very easy, at least in 
most cases; but I cannot be sure of it.

Hope this helps to make things even better!
And thank you again for the original problem :)

Université de Bourgogne
UMR CNRS/uB 6282 Biogéosciences
6 Boulevard Gabriel
21000 Dijon, FRANCE
ivan.calandra at u-bourgogne.fr

Le 21/01/13 03:41, David Winsemius a écrit :
> On Jan 20, 2013, at 3:52 PM, Duncan Murdoch wrote:
>> On 13-01-20 6:23 PM, David Winsemius wrote:
>>> On Jan 20, 2013, at 11:46 AM, Duncan Murdoch wrote:
>>>> On 13-01-20 2:28 PM, Steve Taylor wrote:
>>>>>> From: Duncan Murdoch
>>>>>> Maybe we just need a manual on how to use the existing help
>>>>>> system.  But
>>>>>> I suspect people who won't read the existing manuals won't read that
>>>>>> one, either.
>>>>> Duncan, I assume you're being facetious.  Every R user soon learns
>>>>> to use help() and help.search() or their equivalents.  We don't
>>>>> need a manual to teach that.
>>>> There are other parts of the help system that you don't appear to
>>>> know about.  Run help.start() for the main index page. help() is
>>>> kind of a shortcut to the section labelled "Packages".
>>>> help.search() gets you to "Search Engine & Keywords". There are 15
>>>> other headings to explore as well.
>>> help.search("...")
>>> On my Mac after a very long wait it appears I get all of the functions
>>> in every installed package that have a three-dots argument in their
>>> argument list displayed in the Usage sections. That does not seem very
>>> "help"-ful. I tried limiting with keyword="programming", that did not
>>> appear effective. I wasn't able to figure out from the
>>> help(help.search) page what I need to do to constrict to non-Usage
>>> matches yet expand to items linked from the help.start() page.
>> I don't think you're reading the same "help.search" help page that 
>> I'm reading.  help.search("...") is pretty clearly documented to do a 
>> search for help pages with "alias", "concept" or "title" matching the 
>> regular expression "...", i.e. they have three characters in one of 
>> those.  You should have found every single help page.
>> I don't see anything there that suggests it does a search through the 
>> usage section.  Are you just making stuff up?
> Apparently. I was constructing a theory to explain why my search was 
> taking so long and returning so many pages. With your clarification 
> above I tried a somewhat more successful search. I clearly missed 
> reading the Description paragraph. New strategy:
> help.search("\\.\\.\\.")
> There are only 15 or so hits (could be more or less depending on the 
> composition of the library packages)  and among them is 'dotsMethods'. 
> That looks like a useful page for this topic.  The number of hits 
> would only be half as large if the author of the "labeling" package 
> had not put "..." at the end of 8 of his help page titles.
> Sorry for the noise.
> -- David.
>>> If I just search with a browser for "..." in "Introduction to R" I get
>>> what I consider to be useful material.
>> Yes.  Other ways that should work, but don't:
>> - looking through the index to An Introduction to R.  (The index is 
>> very weak.)  Same for the R Language Definition.
>> - doing a Google search for "R ...".  Stupid Google.
>> Other ways that do work:
>> - Reading the tables of contents for An Introduction to R, or the R 
>> Language Definition.
>> - Reading those manuals.
>> - ?"..." in R-devel, after I commit the changes I described.
>> - Searching with grep through the source files named *.Rd or *.texi. 
>> (For this you need to have the source installed.)
>> I do think the help system is too fragmented, but I also believe it 
>> is better than it used to be.  I am sure that people would make false 
>> claims about it regardless of any improvements, and other people 
>> would complain about any changes, so it's not a priority for me to 
>> work on it any more.
>> Duncan Murdoch
> David Winsemius, MD
> Alameda, CA, USA
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