Sum per hour
We could do it using either POSIXct or chron: library(zoo) # POSIXct z <- zoo(precipitation, as.POSIXct(time, tz = "GMT")) aggregate(z, function(x) as.POSIXct(trunc(x, "hour")), sum) # chron library(chron) z <- zoo(precipitation, as.chron(as.POSIXct(time, tz = "GMT")) aggregate(z, function(x) chron(trunc(times(x), "01:00:00")), sum)
On 5/24/07, jessica.gervais at tudor.lu <jessica.gervais at tudor.lu> wrote:
Dear all,
I have a list of precipitation record and a list of time
I would like to sum them up per hour, or per day.
Does such a function exist ?
example:
time<-c("2000-10-03 14:00:00","2000-10-03 14:10:00","2000-10-03
14:20:00","2000-10-03 15:30:00","2000-10-03 16:40:00","2000-10-03
16:50:00","2000-10-03 17:00:00","2000-10-03 17:10:00","2000-10-03
17:20:00","2000-10-03 18:30:00","2000-10-04 14:00:00","2000-10-04
14:10:00","2000-10-04 14:20:00","2000-10-04 15:30:00","2000-10-04
16:40:00","2000-10-04 16:50:00","2000-10-04 17:00:00","2000-10-04
17:10:00","2000-10-04 17:20:00","2000-10-04 18:30:00")
precipitation<-c(0,0.1,0,0,0,0,0.2,0.3,0.5,6,7,8,9,1,0,0,0,0,1,0)
DATA<-cbind(time,precipitation)
... ?
how to sum up per hour ?
Thanks in advance
Jessica
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