Hello,
See if the following function does it
#----------------------------------------------------------------------
# Round POSIXct date/time
#
round.POSIXct <- function(x, units = c("mins", "5 mins", "10 mins", "15
mins", "quarter hours", "30 mins", "half hours", "hours")){
if(is.numeric(units)) units <- as.character(units)
units <- match.arg(units)
r <- switch(units,
"mins" = 60,
"5 mins" = 60*5,
"10 mins" = 60*10,
"15 mins"=, "quarter hours" = 60*15,
"30 mins"=, "half hours" = 60*30,
"hours" = 60*60
)
H <- as.integer(format(x, "%H")
M <- as.integer(format(x, "%M"))
S <- as.integer(format(x, "%S"))
D <- format(x, "%Y-%m-%d")
secs <- 3600*H + 60*M + S
as.POSIXct(round(secs/r)*r, origin=D)
}
(x <- Sys.time() + 1:10*60)
round(x, "5 mins")
round(x, 5)
round(x, "10 mins")
round(x, "quarter")
round(x, "15 mins")
Hope this helps,
Rui Barradas
Em 09-06-2012 03:04, Phil Hurvitz escreveu:
I wanted to round rather than truncate timestamps
# create a data set to work with
s <- 30 * rnorm(10, 1, 0.1)
gps.timestamp <- Sys.time() + s*1:10
gps.timestamp <- c(round(gps.timestamp[1], "min"), gps.timestamp,
as.POSIXct("2012-06-08 17:32:59"), as.POSIXct("2012-06-08 17:32:30"))
f <- function(gps.timestamp=gps.timestamp, interval=30){
# is the interval a multiple of 60? if so, just round
if(interval %% 60 == 0){
return(data.frame(gps.timestamp,
gps.timestamp.round=round(gps.timestamp, "min")))
}
# a POSIXlt timestamp for fiddling with seconds
lt <- as.POSIXlt(gps.timestamp)
# extract rounded seconds from the timestamp
gps.seconds <- round(lt$sec, 0)
# the number of segments in a minute is 60/interval
seg <- 60/interval
# the cutpoints
rounds <- c(0, 1:seg * interval)
# the "midpoints" for cutting
cuts <- c(-1, 1:seg * 60/seg - interval/2, 60)
# and a numeric representation of the cut position
# (the factor position, really)
numcut <- as.numeric(cut(gps.seconds,cuts))
# the rounded seconds (*not* truncated)
round.seconds <- rounds[numcut]
# truncate the date to the nearest low minute
lt <- lt1 <- trunc(lt, "min")
# add the rounded seconds to the truncated minutes
lt1 <- lt1 + round.seconds
# how does that look?
return(data.frame(gps.timestamp, gps.timestamp.round=lt1))
}
# try it:
f(gps.timestamp, 15)
f(gps.timestamp, 30)
f(gps.timestamp, 10)
-P.
**************************************************************
Philip M. Hurvitz, PhD | Research Assistant Professor | UW-CBE
Urban Form Lab | 1107 NE 45th Street, Suite 535 | Box 354802
University of Washington, Seattle, Washington 98195-4802, USA
phurv...@u.washington.edu | http://gis.washington.edu/phurvitz
"What is essential is invisible to the eye." -de Saint-Exupéry
**************************************************************
I would use package chron and trunc()....
One example from the help of trunc.times (modified):
lirary(chron)
tt <- times(c("12:13:14", "15:46:17"))
trunc(tt, times("00:30:00"))
HTH
Jannis
--- Schatzi <adele_thompson at cargill.com> schrieb am Mo, 9.5.2011:
Von: Schatzi <adele_thompson at cargill.com>
Betreff: [R] Round down to earliest hour or half hour
An: r-help at r-project.org
Datum: Montag, 9. Mai, 2011 14:06 Uhr
I have times and would like to round
down to the earliest 30 minute
increment. For instance, a time of
2011-04-28 09:02:00
(the as.numeric value = 1303999320)
I would like it to be rounded down to:
2011-04-28 09:00:00
(the as.numeric value = 1303999200)
Any ideas of how to do this?
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
