Extract the "levels" attribute from a "ctree" object into a Function that creates a Json object

Question

Thanks to the the following question: Converting toJson R object into a format that fits d3.js tree layout

I have this great code that creates a Json file for d3.js (see below)

I know how to extract split points from a ctree as following:

library(party)
irisct <- ctree(Species ~ .,data = iris)

I just dont know how to implement it in the following code:

   #convert to Json that fits to d3.js layout####
get_ctree_parts <- function(x, ...)
{
  UseMethod("get_ctree_parts")
}

get_ctree_parts.BinaryTree <- function(x, ...)
{
  get_ctree_parts(attr(x, "tree"))
}

get_ctree_parts.SplittingNode <- function(x, ...)
{
  with(
    x,
    list(
      name = toString(nodeID),
      criteria=attr(psplit$splitpoint, "levels"),
      children   = list(get_ctree_parts(x$left),get_ctree_parts(x$right))

    )
  )
}

get_ctree_parts.TerminalNode <- function(x, ...)
{
  with(
    x,
    list(
      name     = paste(nodeID,
                       "weights",sum(weights),
                       "prediction",toString(paste("",toString(round(prediction,3)),"",sep=" ")),
                      # "criteria split",paste((attr(toString(psplit$splitpoint,levels)))), 
                       sep = " ")

    )
  )
}

toJSON(get_ctree_parts(irisct))

output:

{"name":["1"],"criteria":{},"children":[{"name":["2 weights 50 prediction  1, 0, 0 "]},{"name":["3"],"criteria":{},"children":[{"name":["4"],"criteria":{},"children":[{"name":["5 weights 46 prediction  0, 0.978, 0.022 "]},{"name":["6 weights 8 prediction  0, 0.5, 0.5 "]}]},{"name":["7 weights 46 prediction  0, 0.022, 0.978 "]}]}]}

Notice that the "criteria" are left blank : {} while i want them filled with all the levels.

Any help on that would be great !

I don't think `paste((attributes(ct@tree$right$psplit$splitpoint)$levels))` is related here — David Arenburg, Nov 17 '15 at 09:48

score 0 · Accepted Answer · answered Nov 19 '15 at 08:39

I eventually got the info through the splinting node:

#convert to Json that fits to d3.js layout####
get_ctree_parts <- function(x, ...)
{
  UseMethod("get_ctree_parts")
}

get_ctree_parts.BinaryTree <- function(x, ...)
{
  get_ctree_parts(attr(x, "tree"))
}

get_ctree_parts.SplittingNode <- function(x, ...)
{
  with(
    x,
    list(
      name = toString(nodeID),
      variableNames=toString(x$psplit$variableName),
      criteria=toString(attributes(x$psplit$splitpoint)),
     # split   = paste(attributes(get_ctree_parts(x$left$psplit$splitpoint)),attributes(get_ctree_parts(x$right$psplit$splitpoint))),
      children   = list(get_ctree_parts(x$left),get_ctree_parts(x$right))

    )
  )
}

get_ctree_parts.TerminalNode <- function(x, ...)
{
  with(
    x,
    list(
      name     = paste(nodeID,
                       "weights",sum(weights),
                       "prediction",toString(paste("",toString(round(prediction,3)),"",sep=" ")),
                      # "criteria split",paste((attr(toString(psplit$splitpoint,levels)))), 
                       sep = " ")

    )
  )
}

Extract the "levels" attribute from a "ctree" object into a Function that creates a Json object

1 Answers1