Indeed, apply is very flexible and idiomatically R (i.e., the right way to do it) -- but, just a heads up, for datasets with many rows/columns rowMeans and colMeans will be *much* faster (there's loop overhead in the apply family)
Best, Michael On Wed, May 9, 2012 at 3:46 PM, Robert Latest <boblat...@gmail.com> wrote: > On Wed, May 9, 2012 at 4:19 PM, R. Michael Weylandt > <michael.weyla...@gmail.com> wrote: >> Good reproducible example ;-) >> >> Easiest is probably just: >> >> cbind(tencor, ThisRowMean = rowMeans(tencor[, 4:8])) > > Actually, after frying my brain on tapply() and sapply() I found that > just plain apply() does what I need: > > tencor$mean <- apply(tencor[4:8], 1, FUN=mean) > > This way I'm also not tied to just mean() as aggregator but can use > any homemade function (this would have been my followup question had I > followed your advice ;-) > > Thanks! > robert > > ______________________________________________ > 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. ______________________________________________ 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.
