Hi Caroline, >> is.na(strptime("19810329012000",format="%Y%m%d%H%M%S")) >> [1] TRUE
>> The problem was to do with daylight saving time. I need to specify a >> time zone as this time >> doesn't exist in my operating system's current >> time zone. I still think this is odd behaviour >> though! When you look >> at the missing object it doesn't look missing at all. This is just one reason why the posting guide asks you please to provide a small, self-contained, reproducible example of the problem, along with session information, which you never provided: ?sessionInfo sessionInfo() On my system, for instance, your example returns TRUE: > is.na(strptime("19810329012000",format="%Y%m%d%H%M%S")) [1] FALSE > sessionInfo() R version 2.7.1 Patched (2008-06-27 r46012) i386-pc-mingw32 locale: LC_COLLATE=English_South Africa.1252;LC_CTYPE=English_South Africa.1252;LC_MONETARY=English_South Africa.1252;LC_NUMERIC=C;LC_TIME=English_South Africa.1252 attached base packages: [1] grid splines stats graphics grDevices utils datasets methods base other attached packages: [1] exactLoglinTest_1.3.6 vcd_1.0-8 colorspace_0.95 MASS_7.2-42 [5] Design_2.1-1 survival_2.34-1 Hmisc_3.4-3 loaded via a namespace (and not attached): [1] cluster_1.11.11 lattice_0.17-10 tools_2.7.1 Regards, Mark. Caroline Keef-2 wrote: > > > is.na(strptime("19810329012000",format="%Y%m%d%H%M%S")) > [1] TRUE > > The problem was to do with daylight saving time. I need to specify a time > zone as this time doesn't exist in my operating system's current time > zone. I still think this is odd behaviour though! When you look at the > missing object it doesn't look missing at all. > > Caroline > > _________________________________________________________________ > Find the best and worst places on the planet > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. > > -- View this message in context: http://www.nabble.com/Strptime--date-time-classes-tp18362221p18446951.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.