There are two datetime systems available. 1. The POSIXt system in the R base, encompassing the POSIXlt and POSIXct classes. Others have already described where to get info on these.
2. The Bell Labs chron package. Info available at: require(chron) ?chron You may also find this article on chron useful: http://cm.bell-labs.com/cm/ms/departments/sia/dj/papers/chron.pdf A key difference between the two, aside from the specific names and arguments of the functions involved, is that POSIXt works with timezones and with daylight savings time whereas chron does not. I personally use chron for all my stats problems in order to avoid introducing certain subtleties of timezones and daylight savings times. I use POSIXt when I need to manipulate time stamps of files from the operating system since POSIXt provides a close fit to how operating systems handle dates and time. Based on books and documentation for R I believe that most people use POSIXt. --- Date: Fri, 5 Dec 2003 10:40:29 +1100 From: john byrne <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Subject: [R] Processing calendar dates with R I am a beginner in R with a background in SAS. Are there built-in R methods of reading dates for calculating elapsed days between two calendar dates? If so, are there any examples I can browse? Thanks in anticipation. John Byrne. Lecturer in Information Systems. Australian Catholic University. ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
