Dear all, I would be really happy for help with the following because I will treat many columns the same way.
nlevels per ObjektID is what I want, but nlevels returns all levels occurring in cpy.busk$TradArt: buskartant<- aggregate(list(trash = cpy.busk$TradArt), list(ObjektID = cpy.busk$ObjektID), nlevels) But as you can see I use it below anyway. I could use any function instaed of nlevels beacuse now I just want the ObjektID in the right order. Greg Warnes kindly helped me with this solution: group.list <- split(cpy.busk$TradArt, cpy.busk$ObjektID) buskartant$buskartant <- sapply( group.list, function(x) length(unique(x)) ) But the probelm is that unique considers NA as a category, and there is no na.rm argument in unique(). Please give a hint. Thanks a lot in advance! Sincerely, Tord ----------------------------------------------------------------------- Tord Sn�ll Avd. f v�xtekologi, Evolutionsbiologiskt centrum, Uppsala universitet Dept. of Plant Ecology, Evolutionary Biology Centre, Uppsala University Villav�gen 14 SE-752 36 Uppsala, Sweden Tel: 018-471 28 82 (int +46 18 471 28 82) (work) Tel: 018-25 71 33 (int +46 18 25 71 33) (home) Fax: 018-55 34 19 (int +46 18 55 34 19) (work) E-mail: [EMAIL PROTECTED] Check this: http://www.vaxtbio.uu.se/resfold/snall.htm! ------------------------------------------------------------------------ ______________________________________________ [EMAIL PROTECTED] mailing list http://www.stat.math.ethz.ch/mailman/listinfo/r-help
