The date library was written 20 or so years ago. It was a very good first effort, but the newer Date library has superior functionality in nearly every way. The date library is still available, for legacy projects such as yours, but I do not advise it for new work. To answer your specific questions:
1. What you have is a real bug. The underlying C routine that scans through the text returns "0" as a marker for any string it can't figure out, a year of 'abc' or month 'charlie' for example. The S function then turns these into NA. I never, ever thought about year 0. In our longer term studies at Mayo we have birth dates in the 1800s, it is rather surprising that a birth date of 1900 hadn't caught me sometime in the past. I'll fix this. 2. The date library predates the strptime function by over 10 years. It is not a huge surprise that I neglected to include support for it -- my oracular abilities are limited. For an inherited project such as this I would suggest reading the date() documentation as a first step; it is not very long since the package is simple. You want the date.mdy function, which is more straightforward than strptime (with less capabilities of course). Terry Therneau [[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.