如何从随机森林中获取树信息，打包“ party”

Question

I am using R package 'party'. Is there any method to access information of individual tree? Such as which samples (which features are selected, and times) are used for creating the tree, which are the OOB samples, what is the OOB error of the tree. The package 'randomForest' seems to provide part but not complete information. Though RF is a black box, but it could be brighter I think.

Answer 1

Function getTree(rfobj, k=1, labelVar=FALSE) gives the detailed information of each tree. You can print the entire random forest to local file, for example, the following code will print all the information of each tree into a .csv file.

for (i in 1:RandomForestObject$ntree){
    treeFileName <- paste(outputFileDir,'/',forestName,"_tree_", i, '.csv', sep="")
    tree<-getTree(RandomForestObject,i,labelVar=TRUE)
    write.csv(tree, file=treeFileName)
}

Check attributes(RandomForestObj), the 'err.rate' is providing error rate of each tree for each class, this is also what is shown when you plot the error rate of entire forest.