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

[Gabor Grothendieck]

On Thu, Nov 6, 2008 at 12:10 PM, tedzzx <zengzhenxing at gmail.com> 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.

The chron package's times class does not have that restriction:

> library(chron)
> times("10:34:21")
[1] 10:34:21