zoo:rollapply by multiple grouping factors
On Mon, Apr 4, 2011 at 3:40 PM, Mark Novak <mnovak1 at ucsc.edu> wrote:
Thank you very much Gabor! ?It looks like that's gonna work wonderfully. ?I
didn't even know 'ave' existed.
For others out there: ?I only needed to add a comma: ? dat[,c("Site",
"Plot", "Sp")]
Actually, if dd is a data frame dd[, ix] and dd[ix] give the same result. e.g.
dd <- data.frame(a = 1:3, b = 11:13, c = 21:23)
identical(dd[, c("b", "c")], dd[c("b", "c")])
[1] TRUE
Small follow up Q: ?Is there any reason to use 'aggregate' vs. 'ave' in general?
aggregate reduces the data to fewer rows. ave adds a potentially additional column to the original data.
Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com