If you are using the latest version (4.5-25), you will see in rfNews() that that's the problem I need to fix. The package was able to handle ordered factors, but some more stringent checks for factor levels consistency introduced in 4.5-23 broke the support for ordered factors in prediction.
>From the code you've shown, it looks like you are just growing the forest to >evaluate variable importance or other things, instead of predicting other data >(since you set keep.forest=FALSE). If that's the case, you should be fine, as >the problem only happens when you try to call predict() with models that >contain ordered factors as predictors. (Ordered factors are basically treated as numerics in RF: trees only make use of ranks for numeric variables, so there's basically no difference between ordered factors and numeric variables as predictors.) Andy From: Birgit Lemcke > > Hello R-user! > > I am running R 2.7.0 on a Power Book (Tiger). (I am still R and > statistics beginner) > > I try to find the most important variables to divide my dataset as > given in a categorical variable. > > code: > > Test.rf4<-randomForest(Sex~.,na.action=na.roughfix, data=Subset4, > importance=TRUE, proximity=TRUE, ntree=10000, do.trace=1000, > keep.forest=FALSE) > > My dataset contains also ordered factors classified as such. > Is randomForest able to deal with it, does it change anything or is > there no difference in using factors or ordered factors? > > Many thanks in advance > > B. > > Birgit Lemcke > Institut für Systematische Botanik > Zollikerstrasse 107 > CH-8008 Zürich > Switzerland > Ph: +41 (0)44 634 8351 > [EMAIL PROTECTED] > > 175 Jahre UZH > «staunen.erleben.begreifen. Naturwissenschaft zum Anfassen.» > MNF-Jubiläumsevent für gross und klein. > 19. April 2008, 10.00 Uhr bis 02.00 Uhr > Campus Irchel, Winterthurerstrasse 190, 8057 Zürich > Weitere Informationen http://www.175jahre.uzh.ch/naturwissenschaft > > ______________________________________________ > 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. > Notice: This e-mail message, together with any attachme...{{dropped:11}} ______________________________________________ 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.
