Hi:

Here's a toy example:

dat <- seq(as.Date('1990/05/01'), to = as.Date('1990/12/01'), by = 'week')
ddf <- data.frame(datBegin = dat[-length(dat)], datEnd = dat[-1])
ddf <- transform(ddf, datDiff = datEnd - datBegin)

Alternatively, if you don't want the data frame route,
datDiff <- diff(dat)

length(dat)
length(datDiff)

HTH,
Dennis

On Wed, Oct 6, 2010 at 8:07 PM, Santosh Srinivas <santosh.srinivas@gmail.com
> wrote:

> Dear List,
>
> I have a column of dates say:
> test$date1 <- seq(19900511, to = 19900521)
>
> I want the next column to have the number of days between each subsequent
> date i.e days between r(i+1) and r(i)
>
> Any easy way to do this? (I've done it in a roundabout way but just
> wondering if there is any way more than done a loop)
>
> Thanks.
>
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