How to extract the splitting rules for the terminal nodes of ctree()

Question

I have a data set with 6 categorical variables with levels ranging from 5 to 28. I have obtained an output from ctree() (party package) with 17 terminal nodes. I ha

Answer 1

I would recommend to use the new partykit implementation of ctree() rather than the old party package, then you can use the function .list.rules.party(). This is not officially exported, yet, but can be leveraged to extract the desired information.

library("partykit")
airq <- subset(airquality, !is.na(Ozone))
ct <- ctree(Ozone ~ ., data = airq)
partykit:::.list.rules.party(ct)
##                                      3                                      5 
##             "Temp <= 82 & Wind <= 6.9" "Temp <= 82 & Wind > 6.9 & Temp <= 77" 
##                                      6                                      8 
##  "Temp <= 82 & Wind > 6.9 & Temp > 77"             "Temp > 82 & Wind <= 10.3" 
##                                      9 
##              "Temp > 82 & Wind > 10.3"