将ctree输出转换为JSON格式(用于D3树布局)
问题描述:
我正在开发一个需要运行ctree
然后以交互模式绘制它的项目 - 就像'D3.js'树布局一样,我的主要障碍是将ctree
输出转换为json
格式,稍后由javascript使用。将ctree输出转换为JSON格式(用于D3树布局)
以下是我所需要的(与例如从虹膜数据):
> library(party)
> irisct <- ctree(Species ~ .,data = iris)
> irisct
Conditional inference tree with 4 terminal nodes
Response: Species
Inputs: Sepal.Length, Sepal.Width, Petal.Length, Petal.Width
Number of observations: 150
1) Petal.Length <= 1.9; criterion = 1, statistic = 140.264
2)* weights = 50
1) Petal.Length > 1.9
3) Petal.Width <= 1.7; criterion = 1, statistic = 67.894
4) Petal.Length <= 4.8; criterion = 0.999, statistic = 13.865
5)* weights = 46
4) Petal.Length > 4.8
6)* weights = 8
3) Petal.Width > 1.7
7)* weights = 46
现在我想的ctee
输出转换成使用某种算法如下JSON格式(我手工做的),不过,这可能不是将其转换的最佳方式:
{"name" : "Petal.Length <= 1.9 criterion = 1","value": 60, "children" : [
{"name" : "n=50" ,"value": 60},
{"name" : "Petal.Length > 1.9 criterion = 1","value": 60, "children": [
{"name" : "n=46","value": 60 },
{"name" : "Petal.Length > 4.8","value": 60, "children" :[
{"name" : "Petal.Width > 1.7" ,"value": 60},
{"name" : "46" ,"value": 60}
]}] }
]}
这里有两个R的两张照片和D3.js
图:
我已经尝试在ctree对象上使用RJSONIO
,这并没有多大帮助。
有没有人将ctree对象/输出转换为JSON以使用D3.js树布局?如果没有,没有人有任何想法的算法,可以将一个输出转换为另一个?
在此先感谢您的帮助!
答
诀窍是提取irisct
对象的有用位,并且只将它们转换为JSON。事情是这样的:
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(
nodeID = nodeID,
variableName = psplit$variableName,
splitPoint = psplit$splitpoint,
pValue = 1 - round(criterion$maxcriterion, 3),
statistic = round(max(criterion$statistic), 3),
left = get_ctree_parts(x$left),
right = get_ctree_parts(x$right)
)
)
}
get_ctree_parts.TerminalNode <- function(x, ...)
{
with(
x,
list(
nodeID = nodeID,
weights = sum(weights),
prediction = prediction
)
)
}
useful_bits_of_irisct <- get_ctree_parts(irisct)
toJSON(useful_bits_of_irisct)
我想这个答案了通过明智使用unclass
功能。例如:
unclass(irisct)
unclass(attr(irisct, "tree"))
unclass(attr(irisct, "tree")$psplit)
包中的打印方法,party:::print.SplittingNode
和party:::print.TerminalNode
也非常有用的。 (输入party:::print.
并自动完成以查看可用内容。)