Thank you for sharing your experience. The example data I used is from help for "by" function, so every one could have a try.
After using $, the warning message disappeared: aggregate(warbreaks[,1], list(wool = warbreaks$wool, tension=warbreaks$tension),sum) Another approach may be to restart your R. Xingwang Ye Uwe Ligges wrote: > > > Xingwang Ye wrote: >> Dear all, >> When I use aggregate function as: >> >> attach(warpbreaks) >> aggregate(warpbreaks[, 1], list(wool = wool, tension = tension), sum) >> >> The results are right but I get a warning message: >> "number of items to replace is not a multiple of replacement length." >> >> BTW: I use R version 2.4.1 in Ubuntu 7.04. > > > Does not happen for me, neither with R-2.4.1 nor with recent versions > of R. Maybe you have redefined one of the used objects (aggregate, > warpbreaks, wool, tension, sum) in one of your environments? > > BTW: Is is always a bad idea to make much use of attach()... > > Uwe Ligges > > >> Your kind solutions will be great appreciated. >> >> Best wishes >> >> Yours, sincerely, >> Xingwang Ye >> >> ______________________________________________ >> R-help@stat.math.ethz.ch 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@stat.math.ethz.ch 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.
