[R] how to use "..."

Duncan Murdoch murdoch.duncan at gmail.com
Mon Jan 21 00:52:02 CET 2013

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?

> 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

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