On 2 Jan 2003 at 7:58, Sundar Dorai-Raj wrote:
> Tord, > > Tord Snall wrote: > > Dear all, > > I try to summarise my data per category using aggregate, but for > > some reason I get the error message "sum" not meaningful for factors > > even though my vector is numeric. The data set is shown below. > > > > Could someone please give a hint. > > > > Thanks in advance! > > > > Sincerely, > > Tord > > > > > > aggregate requires the first argument to be numeric if you're using > sum > or mean. The way you had it, aggregate was trying to sum your > classification variable as well which is of class `factor'. Try the > following instead. > > > aggregate(list(tallstubbyta = test$tallstubbyta, > list(ObjektID = test$ObjektID), sum) Or aggregate(test$tallstubbyta,list(test$ObjectID),sum) > > Regards, > Sundar Cheers Petr Pikal [EMAIL PROTECTED] [EMAIL PROTECTED] ______________________________________________ [EMAIL PROTECTED] mailing list http://www.stat.math.ethz.ch/mailman/listinfo/r-help
