[R] Script help: Determining Time Difference between two data points.
William Dunlap
wdunlap at tibco.com
Tue Jul 17 23:09:51 CEST 2012
Look at ?as.numeric.difftime
> z <- f(d, d$Score > 150)
> elapsedTime <- z$endDate - z$startDate
> units(elapsedTime)
[1] "secs"
> as.numeric(elapsedTime, units="hours")
[1] 7.616667 0.000000 192.700000 4.366667 62.966667 0.000000 12.500000 0.000000
> as.numeric(elapsedTime, units="days")
[1] 0.3173611 0.0000000 8.0291667 0.1819444 2.6236111 0.0000000 0.5208333 0.0000000
> as.numeric(elapsedTime, units="secs")
[1] 27420 0 693720 15720 226680 0 45000 0
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
> Behalf Of APOCooter
> Sent: Tuesday, July 17, 2012 11:41 AM
> To: r-help at r-project.org
> Subject: Re: [R] Script help: Determining Time Difference between two data points.
>
> Yes! That does exactly what I want it to. Thank you so much.
>
> One question, though, is it possible that the time difference be in hours
> instead of seconds (other than dividing by 3600)? Looking at the code, I
> don't know what I would change.
>
> Does this do what you want?
> > firstInRun <- function(x) c(TRUE, x[-1] != x[-length(x)])
> > lastInRun <- function(x) c(x[-1] != x[-length(x)], TRUE)
> > f <- function(data, condition) {
> + with(data, data.frame(startDate = Date[firstInRun(condition)],
> + endDate = Date[lastInRun(condition)]))
> + }
> > f(d, d$Score > 150)
>
> --
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> Determining-Time-Difference-between-two-data-points-tp4636743p4636786.html
> Sent from the R help mailing list archive at Nabble.com.
>
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