David, Once again, many thanks for your very useful and timely feedback, and for your patience with my learning curve.
Sincerely, Cliff On Mon, Jun 22, 2009 at 7:11 PM, David Winsemius<dwinsem...@comcast.net> wrote: > > On Jun 22, 2009, at 7:55 PM, David Winsemius wrote: > >> >> On Jun 22, 2009, at 6:16 PM, Clifford Long wrote: >> >>> Hi David, >>> >>> I appreciate the advice. I had coerced 'list4' to as.list, but forgot >>> to specify "list=()" in the call to aggregate. I made the correction, >>> and now get the following: >>> >>>> slope.mult = simarray[,1] >>>> adj.slope.value = simarray[,2] >>>> adj.slope.level = simarray[,2] >>>> qc.run.violation = simarray[,5] >>>> simarray.part = cbind(slope.mult, adj.slope.value, qc.run.violation, >>>> adj.slope.level) >>>> list4 = as.list(simarray.part[,4]) >>>> agg.result = aggregate(simarray.part[,3], by=list(list4), FUN = mean) >>> >>> Error in sort.list(unique.default(x), na.last = TRUE) : >>> 'x' must be atomic for 'sort.list' >>> Have you called 'sort' on a list? >>> >>> ... I'm not sure what this means that I've done wrong. I did check >>> 'list4' using "is.list", and get "TRUE" back as an answer, so feel >>> that my mistake is some other fundamental aspect of R that I'm failing >>> to grasp. >>> >>> To your note on 'tapply' ... I did try this as well (actually, tried >>> it first) with no initial success. On your recommendation, I gave >>> tapply another go, and get something recognizable: >>> >>> vtt = tapply(simarray.part[,3], simarray.part[,2], mean) > > > snipped other stuff... > >> >> >>> I would like to be able to plot >>> one against the other. >> >> plot(names(vtt), vtt) > > Or perhaps: > > plot(as.numeric(names(vtt)), vtt) > > -- > > David Winsemius, MD > Heritage Laboratories > West Hartford, CT > > ______________________________________________ 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.