[R] Script help: Determining Time Difference between two data points.

[William Dunlap]

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
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> 
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