Weka Decision tree Java to lists

Question

I want to make a decision tree and break it to lists (name , sign , val). I made the tree with this code :

        //Get File
        BufferedReader reader = new BufferedReader(new FileReader(PATH + "TempArffFile.arff"));

        //Get the data
        Instances data = new Instances(reader);
        reader.close();

        //Setting class attribute 
        data.setClassIndex(data.numAttributes() - 1);

        //Make tree
        J48 tree = new J48();
        String[] options = new String[1];
        options[0] = "-U"; 
        tree.setOptions(options);
        tree.buildClassifier(data);

        //Print tree
        System.out.println(tree);

now I need to break it to arrays how can i do that ?

Example : i get this tree :

title <= 1: bad (4.0)
title > 1
|   positionMatch <= 1
|   |   countryCode <= 1: good (3.0/1.0)
|   |   countryCode > 1: bad (8.0/3.0)
|   positionMatch > 1: good (4.0/1.0)

so i want to get 4 lists from that tree:

• title(<= 1) -> bad
• title(> 1) -> position(<= 1) -> countryCode(<= 1) -> good
• title(> 1) -> position(<= 1) -> countryCode(> 1) -> bad
• title(> 1) -> position(> 1) -> good

How can i do that ?

Answer 1

First the answer with parsing lines seems buggy ( I can't comment on it :(), it seems that it replaces every '|' with the parent clause, but for a tree like :

A | C B | D

The replacement would be wrong, both '|' infront of C and D would be replaced by A.

Also extending class J48 and reimplementing toString() won't help because the tree is actually present in the private variable m_root.

Update:

A better solution to parse the string.

private void string(J48 j48) {

    String tree = j48.toString();
    String[] lines = tree.split("\n");

    List<List<String>> lists = new ArrayList<List<String>>();
    // Break lines into parts.
    for(String line : lines){
        List<String> temp = new ArrayList<String>();
        while(line.indexOf("|") != -1){
            temp.add("|");
            line = line.replaceFirst("\\|", "");
        }
        temp.add(line.trim());
        lists.add(temp);
    }

    // remove first 3 lines of the output.
    for(int i = 0; i < 3; i++){
        lists.remove(0);
    }
    // remove last 4 lines of the output.
    for(int i = 0; i < 4; i++){
        lists.remove(lists.size()-1);
    }

    // This is a ordered list of parents for any given node while traversing the tree.
    List<String> parentClauses = new ArrayList<String>();
    // this describes the depth
    //int depth = -1;

    // all the paths in the tree.
    List<List<String>> paths = new ArrayList<List<String>>();


    for (List<String> list : lists) {
        int currDepth = 0;
        for(int i = 0; i < list.size(); i++){
            String token = list.get(i);
            // find how deep is this node in the tree.
            if (token.equals("|")) {
                currDepth++;
            }
            else {    // now we get to the string token for the node.
                // if leaf, so we get one path..
                if (token.contains(":")) {
                    List<String> path = new ArrayList<String>();
                    for (int index = 0; index < currDepth; index++) {
                        path.add(parentClauses.get(index));
                    }
                    path.add(token);
                    paths.add(path);
                }
                else {
                    // add this to the current parents list
                    parentClauses.add(currDepth, token);
                }
            }
        }
    }

    // print each of the paths.
    for (List<String> path : paths) {
        String str = "";
        for (String token : path) {
            str += token + " AND ";
        }
        LOG.info(str + "\n");
    }

}

Answer 2

Not that nice but maybe better then nothing... Maybe it will give u an idea.

    public static void split(String tree){

    String[] lines = tree.split("\n");
    List<List<String>> lists = new ArrayList<List<String>>(); 
    for(String line : lines){
        List<String> temp = new ArrayList<String>();
        while(line.indexOf("|") != -1){
            temp.add("|");
            line = line.replaceFirst("\\|", "");
        }
        temp.add(line.trim());
        lists.add(temp);
    }

    for(int i = 0; i < 3; i++){
        lists.remove(0);
    }
    for(int i = 0; i < 4; i++){
        lists.remove(lists.size()-1);
    }
    List<String> substitutes = new ArrayList<String>();

    for(List<String> list : lists){
        for(int i = 0; i < list.size(); i++){
            if(!list.get(i).contains(":") && !list.get(i).equals("|") && !substitutes.contains(list.get(i))){
                substitutes.add(list.get(i));
            }
        }
    }
    for(List<String> list : lists){
        for(int i = 0; i < list.size(); i++){
            if(list.get(i).equals("|")){
                list.set(i, substitutes.get(i));
            }
        }
    }
    StringBuilder sb = new StringBuilder();
    for(List<String> list : lists){
        String line = "";
        for(String s : list){
            line = line+" "+s;
        }
        if(line.endsWith(")")){
            sb.append(line+"\n");
        }
    }
    System.out.println(sb.toString());
}

Input

J48 unpruned tree

petalwidth <= 0.6: Iris-setosa (50.0)

petalwidth > 0.6

| petalwidth <= 1.7

| | petallength <= 4.9: Iris-versicolor (48.0/1.0)

| | petallength > 4.9

| | | petalwidth <= 1.5: Iris-virginica (3.0)

| | | petalwidth > 1.5: Iris-versicolor (3.0/1.0)

| petalwidth > 1.7: Iris-virginica (46.0/1.0)

Number of Leaves : 5

Size of the tree : 9

Output:

petalwidth <= 0.6: Iris-setosa (50.0)

petalwidth > 0.6 petalwidth <= 1.7 petallength <= 4.9: Iris-versicolor (48.0/1.0)

petalwidth > 0.6 petalwidth <= 1.7 petallength > 4.9 petalwidth <= 1.5: Iris-virginica (3.0)

petalwidth > 0.6 petalwidth <= 1.7 petallength > 4.9 petalwidth > 1.5: Iris-versicolor (3.0/1.0)

petalwidth > 0.6 petalwidth > 1.7: Iris-virginica (46.0/1.0)