Hi,

Maybe the R version Ryan is using is very old?

cheers,
Paul

Erik Iverson wrote:


Ryan Kinzer wrote:
Erik

Thanks for helping.  Both of them are factors.


That's the problem, they need to be of class Date. See the R NEWS article about Date classes in Volume 4/1.

http://cran.r-project.org/doc/Rnews/

I don't see how they could be factors though, since you shouldn't be able to subtract two factors from each other without a warning at least?

e.g., when I make up factors f1  and f2

>f1 - f2

<snip>

Warning message:
In Ops.factor(f1, f2) : - not meaningful for factors

We would have to have a small, reproducible example to know for sure what's going on...

Best Regards,
Erik

______________________________________________
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.


--
Drs. Paul Hiemstra
Department of Physical Geography
Faculty of Geosciences
University of Utrecht
Heidelberglaan 2
P.O. Box 80.115
3508 TC Utrecht
Phone:  +3130 274 3113 Mon-Tue
Phone:  +3130 253 5773 Wed-Fri
http://intamap.geo.uu.nl/~paul

______________________________________________
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.

Reply via email to