On Mon, May 21, 2012 at 2:00 AM, peter dalgaard <pda...@gmail.com> wrote: [snip] > What the poster probably wanted was something in the vein of > >> nm <- colnames(airquality)[1] >> ff <- formula(bquote(.(as.name(nm))~Month)) >> aggregate(ff, airquality, mean, na.rm=T) > Month Ozone > 1 5 23.61538 > 2 6 29.44444 > 3 7 59.11538 > 4 8 59.96154 > 5 9 31.44828
or perhaps to use an implicit loop (since looping seemed to be part of it all): results <- lapply(c("Ozone", "Solar.R"), function(n) { aggregate(. ~ Month, airquality[, c(n, "Month")], mean, na.rm = TRUE) }) ## print results results ## untested code based on OPs original example vars <- colnames(df)[c(10,12,16,18,20,21,24:29,45)] results <- lapply(vars, function(n) { aggregate(. ~ x1 + x2 + x3, df[, c(n, "x1", "x2", "x3")], mean, na.rm = TRUE) }) ## print results results Cheers, Josh > -- > Peter Dalgaard, Professor > Center for Statistics, Copenhagen Business School > Solbjerg Plads 3, 2000 Frederiksberg, Denmark > Phone: (+45)38153501 > Email: pd....@cbs.dk Priv: pda...@gmail.com > > ______________________________________________ > 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. -- Joshua Wiley Ph.D. Student, Health Psychology Programmer Analyst II, Statistical Consulting Group University of California, Los Angeles https://joshuawiley.com/ ______________________________________________ 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.