df<-data.frame(
decision=c("1","1","1","2","2","2","3","3","3"),
state=c("a","b","c","a","b","c","a","b","c"),
cost=c(300,160,-50,260,160,10,296,176,-4)
)
如何用rpart得到类似下面数据框df结构的决策树啊？
decision state cost
1 1 a 300
2 1 b 160
3 1 c -50
4 2 a 260
5 2 b 160
6 2 c 10
7 3 a 296
8 3 b 176
9 3 c -4
