On Aug 1, 2012, at 5:33 AM, Rui Barradas wrote:
Hello,
Try the following.
dat <- structure(list(date = c("2000-01-05 00:00:00", "2000-01-05
01:00:00",
"2000-01-05 05:00:00", "2000-01-05 06:00:00", "2000-01-05 07:00:00",
"2000-01-05 08:00:00", "2000-01-05 09:00:00", "2000-01-05 10:00:00",
"2000-01-05 11:00:00", "2000-02-05 00:00:00", "2000-02-05 01:00:00",
"2000-02-05 05:00:00", "2000-02-05 06:00:00", "2000-02-05 07:00:00",
"2000-02-05 08:00:00", "2000-02-05 09:00:00", "2000-02-05 10:00:00",
"2000-02-05 11:00:00"), value = c(1, 1, 3.6, 3.6, 2.2, 2.2, 2.2,
2.2, 2.2, 1, 1, 3.6, 3.6, 2.2, 2.2, 2.2, 2.2, 2.2)), .Names =
c("date",
"value"), row.names = c(NA, -18L), class = "data.frame")
library(chron) # needed for times()
I don't think you do need to use chron. Once the date-times are
available as POSIXt values, you can just use the formated times for
comparisons:
> dat$date <- as.POSIXct( dat$date)
> tm <- format(dat$date, format="%H:%M:%S")
> inx <- "00:00:00" <= tm & tm <= "05:00:00"
> dat[inx, ]
date value
1 2000-01-05 00:00:00 1.0
2 2000-01-05 01:00:00 1.0
3 2000-01-05 05:00:00 3.6
10 2000-02-05 00:00:00 1.0
11 2000-02-05 01:00:00 1.0
12 2000-02-05 05:00:00 3.6
--
David.
dat$date <- as.POSIXct(dat$date)
tm <- times(format(dat$date, format="%H:%M:%S"))
inx <- times("00:00:00") <= tm & tm <= times("05:00:00")
dat[inx, ]
Hope this helps,
Rui Barradas
Em 01-08-2012 07:48, Васильченко Александр
escreveu:
Hello
I have dataframe
How to remove dates in hourly time seriesThe example time series
likedate
value
2000-01-05 00:00:00 1.0
2000-01-05 01:00:00 1.0
2000-01-05 05:00:00 3.6
2000-01-05 06:00:00 3.6
2000-01-05 07:00:00 2.2
2000-01-05 08:00:00 2.2
2000-01-05 09:00:00 2.2
2000-01-05 10:00:00 2.2
2000-01-05 11:00:00 2.2
2000-02-05 00:00:00 1.0
2000-02-05 01:00:00 1.0
2000-02-05 05:00:00 3.6
2000-02-05 06:00:00 3.6
2000-02-05 07:00:00 2.2
2000-02-05 08:00:00 2.2
2000-02-05 09:00:00 2.2
2000-02-05 10:00:00 2.2
2000-02-05 11:00:00 2.2
And I take interval for example from 00:00:00 to 05:00:00.
date value
2000-01-05 00:00:00 1.0
2000-01-05 01:00:00 1.0
2000-01-05 05:00:00 3.6
2000-02-05 00:00:00 1.0
2000-02-05 01:00:00 1.0
2000-02-05 05:00:00 3.6
Regards, Aleksander.
David Winsemius, MD
Alameda, CA, USA
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