One way for doing it would be to combine the columns using paste and then
use tapply to get the means.
For example:
set.seed(32341)
a1 = sample(c("a","b"), 100,replace = T)
a2 = sample(c("a","b"), 100,replace = T)
y = rnorm(100)
tapply(y,paste(a1,a2), mean)
----------------Contact
Details:-------------------------------------------------------
Contact me: tal.gal...@gmail.com | 972-52-7275845
Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) |
www.r-statistics.com (English)
----------------------------------------------------------------------------------------------
On Thu, Oct 6, 2011 at 8:40 AM, SML <paral...@lafn.org> wrote:
> Hello:
>
> Is there a way to get a mean from values stored in different rows?
>
> The data looks like this:
> YEAR-1, JAN, FEB, ..., DEC
> YEAR-2, JAN, FEB, ..., DEC
> YEAR-3, JAN, FEB, ..., DEC
>
> What I want is the mean(s) for just the consecutive winter months:
> YEAR-1.DEC, YEAR-2.JAN, YEAR-2.FEB
> YEAR-2.DEC, YEAR-3.JAN, YEAR-3.FEB
> etc.
>
> Thanks.
>
> ______________________________________________
> 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.
