R/extractRules.R

In inTrees: Interpret Tree Ensembles

extractRules <-
function(treeList,X,ntree=100,maxdepth=6,random=FALSE,digits=NULL){
 if(is.numeric(digits)) digits <- as.integer(abs(digits))
 
 levelX = list()
 for(iX in 1:ncol(X))
 levelX <- c(levelX,list(levels(X[,iX])))
 # X <- NULL; target <- NULL
 ntree=min(treeList$ntree,ntree)
 allRulesList = list()
 for(iTree in 1:ntree){
 if(random==TRUE){max_length = sample(1:maxdepth,1,replace=FALSE)}else{
 max_length = maxdepth}
 rule = list(); count = 0; rowIx = 1; 
 # tree = getTree(rf,iTree,labelVar=FALSE)
 tree <- treeList$list[[iTree]]
 if(nrow(tree)<=1) next # skip if there is no split
 ruleSet = vector("list", length(which(tree[,"status"]==-1)))
 res = treeVisit(tree,rowIx = rowIx,count,ruleSet,rule,levelX,length=0,max_length=max_length,digits=digits)
 allRulesList = c(allRulesList, res$ruleSet)
 }
allRulesList <- allRulesList[!unlist(lapply(allRulesList, is.null))]
cat(paste(length(allRulesList)," rules (length<=",  
max_length, ") were extracted from the first ", ntree," trees.","\n",sep=""))

rulesExec <- ruleList2Exec(X,allRulesList)
return(rulesExec)
}