> -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] > On Behalf Of David Fox > Sent: Tuesday, January 28, 2014 5:15 PM > To: r-help@r-project.org > Subject: [R] Difference between two datetimes > > I have a data frame with variable "datetime" which is of class POSIXct. > Consecutive observations are separated by 30 minutes. > However, some of the differences reported by R give unexpected results. > For example consider the following two consecutive entries: > > > par.dat$datetime[5944] > [1] "2010-04-04 02:30:00 EST" > > > par.dat$datetime[5945] > [1] "2010-04-04 03:00:00 EST" > > When I examine the difference, R reports 1.5 hours instead of 30 minutes: > > > par.dat$datetime[5945]-par.dat$datetime[5944] > Time difference of 1.5 hours > > On further investigation it appears there's something peculiar to this > particular date. Other years work fine, eg: > > as.POSIXct("2011-04-04 03:00:00")- as.POSIXct("2011-04-04 02:30:00") > Time difference of 30 mins > > > as.POSIXct("2012-04-04 03:00:00")- as.POSIXct("2012-04-04 02:30:00") > Time difference of 30 mins > > > as.POSIXct("2009-04-04 03:00:00")- as.POSIXct("2009-04-04 02:30:00") > Time difference of 30 mins > > But when I use 2010 I get a difference of 1.5 hours: > > > as.POSIXct("2010-04-04 03:00:00")- as.POSIXct("2010-04-04 02:30:00") > Time difference of 1.5 hours > > > > > > > Any suggestions? > Thanks, > David Fox. >
Daylight savings time change in Australia? Dan Daniel Nordlund Bothell, WA USA ______________________________________________ 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.
