[R] R Experts

[Erik Iverson]

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