Plotting a rpart decision tree modell with the sunburst view

Question

I found a way to plot a decision tree solution from rpart with the sunburstR-package. To plotting a sunburst it is necessary to have data.frame which represents a sequence. I modified the decision tree result to a sequence like below

Result of the decision tree

rpart(Species~.,data=iris)

n= 150 

node), split, n, loss, yval, (yprob)
      * denotes terminal node

1) root 150 100 setosa (0.33333333 0.33333333 0.33333333)  
  2) Petal.Length< 2.45 50   0 setosa (1.00000000 0.00000000 0.00000000) *
  3) Petal.Length>=2.45 100  50 versicolor (0.00000000 0.50000000 0.50000000)  
    6) Petal.Width< 1.75 54   5 versicolor (0.00000000 0.90740741 0.09259259) *
    7) Petal.Width>=1.75 46   1 virginica (0.00000000 0.02173913 0.97826087) * 

Sequence for the sunburst:

sequences_1<-1
sequences_1<-data.frame(sequences_1)
sequences_1[1:3,]<-1
sequences_1$V1[1]<-"Petal.Length<_2.45-setosa"
sequences_1$V1[2]<-"Petal.Length>=2.45-Petal.Width<_1.75_54_5-versicolor"
sequences_1$V1[3]<-"Petal.Length>=2.45-Petal.Width>=1.75_46_1-virginica"
sequences_1$V2[1]<-50
sequences_1$V2[2]<-54
sequences_1$V2[3]<-46
sequences_1$sequences_1<-NULL

Plotting Sunburst:

library(sunburstR)
sunburst(sequences_1,count=TRUE)

The sequence for the sunburst plot, I did manually. Do someone know how to build the sequence automatically like above from the result of the rpart decision tree?

Answer 1

d3r provides a function d3_party to convert rpart/partykit into a d3 hierarchy. sunburst can use the result of d3_party with one minor modification to change "rule" to "name". This is not ideal but in most cases will work flawlessly.

library(rpart)
library(d3r)
# d3_party requires partykit
# install.packages("partykit")
library(sunburstR)

rp <- rpart(Species~.,data=iris)
rp_d3 <- d3_party(rp)

# one trick/hack required since sunburst expects
#   name but d3_party gives rule
#   this is ugly but let's replace all "rule" with "name"
#   with gsub
rp_d3 <- gsub(
  x = rp_d3,
  pattern = '"rule":',
  replacement = '"name":'
)

sunburst(
  rp_d3,
  valueField = "n",
  sumNodes = FALSE,
  count = TRUE,
  legend = FALSE
)