Re: [Rd] chron vs. POSIX

From: Gabor Grothendieck <>
Date: Sat 15 Jul 2006 - 17:37:23 GMT

On 7/15/06, Duncan Murdoch <> wrote:
> On 7/15/2006 1:01 PM, Gabor Grothendieck wrote:
> > On 7/14/06, Duncan Murdoch <> wrote:
> >> On 7/14/2006 3:38 PM, Sebastian Luque wrote:
> >>> Hi,
> >>>
> >>> One of the big decisions when writing code is how to handle dates and
> >>> times. Gabor Grothendieck provided an excellent overview of the issue in
> >>> his R News 4/1 (2004) article, and many users and developers are probably
> >>> using it as a guide. The proposed guideline is to use the simplest class
> >>> required; as Gabor put it "use Date if possible, otherwise use chron, and
> >>> otherwise use POSIX".
> >>>
> >>> This seems to me a very efficient strategy, judging from my own
> >>> experiences and those of others users. All but the simplest calculations
> >>> with POSIX objects demand great care, due to time zone and and daylight
> >>> savings considerations. Therefore, I've always chosen chron for
> >>> relatively complex projects, where I don't need to deal with time zones or
> >>> daylight savings problems. The ease with which objects can be switched
> >>> from numeric to chron representations is a major advantage IMHO¹.
> >>>
> >>> If Gabor's recommendations are to be followed, wouldn't it make sense to
> >>> include chron in base R? Given that flexibility for handling time
> >>> variables is so fundamental, the addition of chron to base R would provide
> >>> users everything they need to work with time, without the need to rely on
> >>> an external package. What do others think?
> >> Putting something into base R essentially means that it is to be taken
> >> over by R core. I think chron is being adequately maintained now (the R
> >> maintainer is already a member of R core), so I don't see a need for that.
> >>
> >> I don't see a problem having a package on CRAN. If it's a good package
> >> and people realize that it's good, and it remains available for others
> >> to use, then what problem is being solved?

> >
> > I think the problem is that there is nothing to signal its importance. Perhaps
> > chron should be added to the "recommended" package list.
> I think that would be preferable to making it a base package, but it's
> not the only way to publicize it. Why not add something to the Wiki to
> compare the various possibilities for storing dates and times?

As a recommended package it would be included in all binary releases ensuring access without a separate install and would provide more official endorsement. mailing list Received on Sun Jul 16 03:41:39 2006

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