From spencer.graves at structuremonitoring.com  Thu Aug 19 17:43:49 2010
From: spencer.graves at structuremonitoring.com (Spencer Graves)
Date: Thu, 19 Aug 2010 08:43:49 -0700
Subject: [Rd] c.POSIXct
In-Reply-To: <AANLkTi=m2Ti5bWVGMT=RH0xA7WF=A=1cf1jZrNjcJs9Z@mail.gmail.com>
References: <AANLkTinGcXRQd5+Xmo2ad5HoofdbzhZbEaSznAgCL3vO@mail.gmail.com>	<AANLkTin=8k4UfBqzjQmHa9ntQP3V9zhuhsfkL_qzZyWi@mail.gmail.com>	<D611103AA7EE3B4DAE7F7D49C72B291A02C7E497@EXMAIL2.bocad.bank-banque-canada.ca>
	<AANLkTi=m2Ti5bWVGMT=RH0xA7WF=A=1cf1jZrNjcJs9Z@mail.gmail.com>
Message-ID: <4C6D5135.5010105@structuremonitoring.com>

  Hi, Gabor, Paul, et al.:


       For classes that did not supply a "ca" method, I'd rather see the 
default being to start with the corresponding  "c" method followed by an 
effort to preserve attributes to the maximum extent feasible.  I'm not 
sure the best defaults, but at the moment, I would expect that 
attributes like "dim" and "dimnames" should always be dropped.  The 
current default "c" method preserves "names" appropriately.


       What do you think about including another argument to 
"checkAttributes"?  I'm not sure what the options should be nor what 
should be the default, but one option should throw and error if any 
contradiction was found while another would take all attributes from the 
first argument and ignore others.


       Best Wishes,
       Spencer Graves


On 8/19/2010 7:32 AM, Gabor Grothendieck wrote:
> On Thu, Aug 19, 2010 at 10:16 AM, Paul Gilbert
> <pgilbert at bank-banque-canada.ca>  wrote:
>> I used to get caught by this c() behaviour often, but now I do expect it to drop attributes. I think it would break many things if you change it, and force people to write different code when they really do want to drop attributes. When you want new behaviour it is usually better to define a new function, ca() maybe?
>>
> That would work if ca defaulted to c for those classes that did not
> supply a ca method.
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>


-- 
Spencer Graves, PE, PhD
President and Chief Operating Officer
Structure Inspection and Monitoring, Inc.
751 Emerson Ct.
San Jos?, CA 95126
ph:  408-655-4567



[Rd] c.POSIXct
Spencer Graves