Hello, I'm working with POSIXct objects, and I found some strange behavior. I'm trying to extract a 30min time series from a POSIXct vector, and it seems that R is having problems with daylight saving time:
> test [1] "2002-03-31 01:15:00 CET" "2002-03-31 01:30:00 CET" [3] "2002-03-31 01:45:00 CET" "2002-03-31 03:00:00 CEST" [5] "2002-03-31 03:15:00 CEST" "2002-03-31 03:30:00 CEST" [7] "2002-03-31 03:45:00 CEST" "2002-03-31 05:00:00 CEST" [9] "2002-03-31 05:15:00 CEST" "2002-03-31 05:30:00 CEST" [11] "2002-03-31 05:45:00 CEST" "2002-03-31 05:00:00 CEST" [13] "2002-03-31 05:15:00 CEST" "2002-03-31 05:30:00 CEST" [15] "2002-03-31 05:45:00 CEST" "2002-03-31 06:00:00 CEST" [17] "2002-03-31 06:15:00 CEST" "2002-03-31 06:30:00 CEST" [19] "2002-03-31 06:45:00 CEST" "2002-03-31 07:00:00 CEST" #just a time series. > ft<-(as.integer(test)%%1800)==0 > ft [1] FALSE TRUE FALSE TRUE FALSE TRUE FALSE TRUE FALSE TRUE FALSE TRUE [13] FALSE TRUE FALSE TRUE FALSE TRUE FALSE TRUE #And now, when extracting the right entries out of "test": > test[ft] [1] "2002-03-31 01:30:00 CET" "2002-03-31 03:00:00 CEST" [3] "2002-03-31 03:30:00 CEST" "2002-03-31 05:00:00 CEST" [5] "2002-03-31 05:30:00 CEST" "2002-03-31 05:00:00 CEST" [7] "2002-03-31 05:30:00 CEST" "2002-03-31 06:00:00 CEST" [9] "2002-03-31 06:30:00 CEST" "2002-03-31 07:00:00 CEST" Here, [4] and [5] are wrong... BTW, is there a way to ask R to use another time zone than the one your computer is in? I'm working on data that do not use daylight saving time, but my computer does (west european time zone) and that's quite confusing when importing/exporting. Thanks, Wouter Buytaert ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
