Hi, For a project I try to keep everything in normal time, not daylight saving time, to prevent problem when instruments collected data during the nights when we go from DST to normal time.
But sometimes R tricks me and I do not know how to prevent it. This is one example: lights_on = as.POSIXct(c("2011-05-06 04:09:26", "2011-05-07 04:07:53", "2011-05-08 04:06:21", "2011-05-09 04:04:51", "2011-05-10 04:03:22", "2011-05-11 04:01:55", "2011-05-12 04:00:30", "2011-05-13 03:59:06", "2011-05-14 03:57:45", "2011-05-15 03:56:25", "2011-05-16 03:55:07"), tz="EST") # not DST lights_off = as.POSIXct(c("2011-05-05 18:56:54", "2011-05-06 18:58:19", "2011-05-07 18:59:44", "2011-05-08 19:01:08", "2011-05-09 19:02:32", "2011-05-10 19:03:55", "2011-05-11 19:05:18", "2011-05-12 19:06:40", "2011-05-13 19:08:01", "2011-05-14 19:09:22", "2011-05-15 19:10:42" ), tz="EST") # not DST (a = lights_on[c(1,5)]) # not DST [1] "2011-05-06 04:09:26 EST" "2011-05-10 04:03:22 EST" (b = lights_off[c(2,6)]) # not DST [1] "2011-05-06 18:58:19 EST" "2011-05-10 19:03:55 EST" (x = c(lights_off[2], lights_on[2])) # suddenly DST [1] "2011-05-06 19:58:19 EDT" "2011-05-07 05:07:53 EDT" Why did x end up in DST? How could I prevent it? Thanks in advance, Denis ______________________________________________ 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.