[R] Datetimes differences

[Prof Brian Ripley]

On Wed, 11 Jan 2006 bonneu at cict.fr wrote:

> I want to obtain datetime differences in mins in an other column, in front of my
> datetimes. I have tried this :
>
> T1 <- c("12/31/03 23:49","1/1/04 1:14","1/1/04 0:02")
> T2 <- c("1/1/04 0:58","1/1/04 1:16","")
> toto <- data.frame(T1,T2)
> toto
>
> y <- strptime(T1,"%m/%d/%y %H:%M")
> x <- strptime(T2,"%m/%d/%y %H:%M")
> difftime(x,y)
>
>
> but, i don't know how can i do in order to obtain something like this :
>
> ans <- c(69,2,NA)
> res <- data.frame(T1,T2,ans)
> res

data.frame(T1, T2, mins=as.numeric(difftime(x,y, units="mins")))

-- 
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