[R] Units of Difference Between Two Dates

[Prof Brian Ripley]

On Thu, 15 May 2008, Tom La Bone wrote:

>
> I would like all three of these calculations to give an answer in days (or at
> least the same units):
>
>> as.POSIXct("1971-08-01 00:00:00") - as.POSIXct("1971-08-01 00:00:00")
> Time difference of 0 secs
>>
>> as.POSIXct("1971-08-01 12:00:00") - as.POSIXct("1971-08-01 00:00:00")
> Time difference of 12 hours
>>
>> as.POSIXct("1971-09-01 00:00:00") - as.POSIXct("1971-08-01 00:00:00")
> Time difference of 31 days
>>
>
> What is the best way to do this?

Use difftime() explicitly.

-- 
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)
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