This is daylight savings time issue. Use chron or set your TZ environment variable to a standard-time-only timezone (or don't enter nonexistent time values for the timezone in which you wish to compute). --------------------------------------------------------------------------- Jeff Newmiller The ..... ..... Go Live... DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go... Live: OO#.. Dead: OO#.. Playing Research Engineer (Solar/Batteries O.O#. #.O#. with /Software/Embedded Controllers) .OO#. .OO#. rocks...1k --------------------------------------------------------------------------- Sent from my phone. Please excuse my brevity.
Adrienne Wootten <amwoo...@ncsu.edu> wrote: R-listers, I have noticed several posts on issues with difftime producing NA's but they have been for older versions of R. Here's the issue associated with difftime that I am dealing with in R 2.12.2. > preciptime = strptime("01/10/2007 14:00",format="%m/%d/%Y %H:%M") > class(preciptime) [1] "POSIXlt" "POSIXt" > # Now using difftime, this is what happens > > difftime(strptime("03/11/2007 01:00",format="%m/%d/%Y > %H:%M"),preciptime,units="hours") Time difference of 1427 hours > difftime(strptime("03/11/2007 02:00",format="%m/%d/%Y > %H:%M"),preciptime,units="hours") Time difference of NA hours > difftime(strptime("03/11/2007 03:00",format="%m/%d/%Y > %H:%M"),preciptime,units="hours") Time difference of 1428 hours This doesn't make sense to me since both times used in difftime are in the same format after using strptime, but the differences are coming out wrong. It should be 1427, 1428, and 1429, so I'm confused as to how to fix this. The idea with the program is to compute the time in hours since last rainfall, so everything gets thrown off with this producing NA's. For reference, Operating system is Windows 7 Enterprise, R is version 2.12.2 (64-bit), any guidance is appreciated. Thanks in advance! A -- Adrienne Wootten Graduate Research Assistant State Climate Office of North Carolina Department of Marine, Earth and Atmospheric Sciences North Carolina State University _____________________________________________ 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. [[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.