[R] How to manipulate the time data without the date?

[Prof Brian Ripley]

Why not give it an arbitrary date such 2008-01-01?

On Thu, 6 Nov 2008, tedzzx wrote:

>
> Hi,all
>
> I only got the time data such as:
> tms<-c("19:30:23","18:39:10".....)
>
> I want to manipulate this time series data. For example, plus one second(or
> minute) or minus one second
>
> This data only has the time(h:m:s), without the date. I know that there are
> chron package, ISOPix class and the timeDate class, but all these class need
> the input of date.

And in base R there is POSIXct.

> How can we manipulate the time data without the date?

Not really, as DST changes mean which day does matter.  But all other days 
will be the same.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595