Tree package on R 1.4.1
On Tue, 23 Apr 2002 baba at muj.biglobe.ne.jp wrote:
Dear R-users I would like to apply classification and regression tree(CART) to the following data.
You can use a classification tree or a regression tree, but not a `classification and regression tree'. Your usage below suggests you want a regression tree.
I have some question on using 'tree' package. The data contains one response variable Y and five explanatory variables. The explanatory variable "x2" is categorical and not ordinal. But, the result obtained after running following R code has indicated that x2 is regard as continuous variable.
Well, that *is* what you asked for! You read x2 as a numeric variable in scan. ?tree will tell you how to specify a categorical variable (via a factor).
I think that CART procedure can be available to categorical and continuous variables. How can I correct the R code such that x2 is regard as categorical and not ordinal?
Try Ex6$x2 <- factor(Ex6$x2). Note that the rpart package is the recommended way to perform tree-based analyses in R, and that `CART' is a trademark of a commercial package.
By all means, reply me your suggestion or comments.
Thanks and best regards,
Baba
----------beginning of R code --------------------
inputlist <- list(Y=0, x1=0, x2=0, x3=0,x4=0,x5=0)
# inputlist <- list(Y=0, x1=0, x2="", x3=0,x4=0,x5=0)
Ex6 <- scan("c:\\data\\CART\\EX6.txt",inputlist)
Ex6.ltr <- tree(Y ~ x1 + x2 +x3 + x4 +x5 ,Ex6)
----------end of R code ---------------------------
Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._