From jeff.a.ryan at gmail.com  Wed Sep 17 22:19:20 2008
From: jeff.a.ryan at gmail.com (Jeff Ryan)
Date: Wed, 17 Sep 2008 15:19:20 -0500
Subject: [Rd] Dates in C api
In-Reply-To: <575EAD86322DA342B50FE422364A9F52082D528B@NYWEXMB27.msad.ms.com>
References: <575EAD86322DA342B50FE422364A9F52082D528B@NYWEXMB27.msad.ms.com>
Message-ID: <e8e755250809171319h15fc8461yfd5c7ab1531ad89e@mail.gmail.com>

If you are looking for examples of handling dates/times (specifically
POSIXct) within C code, the dev branch of xts has quite a bit of code
now.

http://r-forge.r-project.org/plugins/scmsvn/viewcvs.php/dev/pkg/src/?root=xts

Assigning the class (or any attribute) within the C code will be much
faster than doing it outside of C, at least in my experience with
larger data.

setAttrib(ans, R_ClassSymbol, mkString("Date"))

HTH
Jeff

On Wed, Sep 17, 2008 at 12:24 PM, Lee, Philip (IT)
<Phil.Lee at morganstanley.com> wrote:
> r-devel,
>
> I've been trying to write a C plugin for R, and I'm struggling to
> understand how dates are represented.
>
> I can create a date in R:
>> mydate<-as.Date(1, origin="1900-01-01") mydate
> [1] "1900-01-02"
>
> When I pass my date to a plugin, though, it's type is that of a real.
> There doesn't seem to be a date type in Rinternals.h, is there a way to
> recognize that a value is a date rather than a real?
>
> Equally, does anyone know if it's possible to create date values in the
> C api?
>
> Thanks,
> Phil Lee
>
> Philip Lee
> Morgan Stanley | Technology
> 750 Seventh Avenue, 12th Floor | New York, NY  10019
> Phil.Lee at morganstanley.com
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-- 
Jeffrey Ryan
jeffrey.ryan at insightalgo.com

ia: insight algorithmics
www.insightalgo.com



[Rd] Dates in C api
Jeff Ryan