Dear R-users, I use unlist of POSIX dates to extract the year, hour etc. With that I can search for files in my database which are in the form 'yyyymmddhh_synops.txt' However, I get stucked during midnight where unlist just gives NA's. The script is given below; the problem accurs at acc.period[16] (midnight). However when I write out the character, unlist works well. But as.character(acc.period[16]) is not the solution....
> dates=seq(as.Date("2006-03-01"), as.Date("2006-11-01"), "days") > i=1 > begin=paste(dates[i]-1,"09:00:00") > end=paste(dates[i],"08:00:00") > acc.period=seq(as.POSIXct(begin),as.POSIXct(end),"hour") > > unlist(strptime(acc.period[15],format="%Y-%m-%d %H:%M:%S")) sec min hour mday mon year wday yday isdst 0 0 23 28 1 106 2 58 0 > unlist(strptime(acc.period[16],format="%Y-%m-%d %H:%M:%S")) sec min hour mday mon year wday yday isdst NA NA NA NA NA NA NA NA -1 > unclass(strptime(acc.period[16],format="%Y-%m-%d %H:%M:%S")) $sec [1] NA $min [1] NA $hour [1] NA $mday [1] NA $mon [1] NA $year [1] NA $wday [1] NA $yday [1] NA $isdst [1] -1 > > a="2006-03-01 00:00:00" > unlist(strptime(a,format="%Y-%m-%d %H:%M:%S")) sec min hour mday mon year wday yday isdst 0 0 0 1 2 106 3 59 0 > > sessionInfo() R version 2.4.0 (2006-10-03) i386-pc-mingw32 locale: LC_COLLATE=English_United States.1252;LC_CTYPE=English_United States.1252;LC_MONETARY=English_United States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252 attached base packages: [1] "methods" "stats" "graphics" "grDevices" "utils" "datasets" [7] "base" Thanks in advance! Hanneke -- --------------------------------------------- ir J.M. (Hanneke) Schuurmans PhD student Hydrology Department of Physical Geography Faculty of Geosciences - Universiteit Utrecht P.O. Box 80115 3508 TC Utrecht T +31 (0)30 2532988 F +31 (0)30 2531145 W www.geo.uu.nl/staff/schuurmans ______________________________________________ R-help@stat.math.ethz.ch 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.