library (rpart)
library(partykit)

data("Titanic", package = "datasets")
ttnc <- as.data.frame(Titanic)
ttnc <- ttnc[rep(1:nrow(ttnc), ttnc$Freq), 1:4]
names(ttnc)[2] <- "Gender"

rp <- rpart(Survived ~ Gender + Age + Class,  data = ttnc)
prp <- as.party(rp)

prp[5]

data_party(prp, id = 5)

ttnc$Node <- predict(prp, newdata = ttnc, type = "node")

subtree <- subset(ttnc, Node == 5)