[R] Class for time of day?

[Gabor Grothendieck]

There is a times class in the chron package.  Times are measured
in fractions of a day so 1/24 is one hour.

> library(chron)
> dt <- Sys.time()
> tt <- times(format(dt, "%H:%M:%S"))
> tt
[1] 12:27:46
> tt + 1/24
[1] 13:27:46

There is an article on dates and times in R News 4/1.

On Wed, May 20, 2009 at 10:57 AM, Stavros Macrakis
<macrakis at alum.mit.edu> wrote:
> What is the recommended class for time of day (independent of calendar
> date)?
>
> And what is the recommended way to get the time of day from a POSIXct
> object? (Not a string representation, but a computable representation.)
>
> I have looked in the man page for DateTimeClasses, in the Time Series
> Analysis Task View and in Spector's Data Manipulation book but haven't found
> these. Clearly I can create my own Time class and hack around with the
> internal representation of POSIXct, e.g.
>
>    days <- unclass(d)/(24*3600)
>    days-floor(days)
>
> and write print.Time, `-.Time`, etc. etc. but I expect there is already a
> standard class or CRAN package.
>
>           -s
>
>        [[alternative HTML version deleted]]
>
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