decision-trees

Create decision trees and use them to predict new cases.

Currently implemented ID3 algorithm only. Based on lectures of Victor Lavrenko

Usage

const ID3 = require('decision-trees');

const examples = [
    {outlook: 'sunny', humidity: 'high', wind: 'weak', play: false},
    {outlook: 'sunny', humidity: 'high', wind: 'strong', play: false},
    {outlook: 'overcast', humidity: 'high', wind: 'weak', play: true},
    {outlook: 'rain', humidity: 'high', wind: 'weak', play: true},
    {outlook: 'rain', humidity: 'normal', wind: 'weak', play: true},
    {outlook: 'rain', humidity: 'normal', wind: 'strong', play: false},
    {outlook: 'overcast', humidity: 'normal', wind: 'strong', play: true},
    {outlook: 'sunny', humidity: 'high', wind: 'weak', play: false},
    {outlook: 'sunny', humidity: 'normal', wind: 'weak', play: true},
    {outlook: 'rain', humidity: 'normal', wind: 'weak', play: true},
    {outlook: 'sunny', humidity: 'normal', wind: 'strong', play: true},
    {outlook: 'overcast', humidity: 'high', wind: 'strong', play: true},
    {outlook: 'overcast', humidity: 'normal', wind: 'weak', play: true},
    {outlook: 'rain', humidity: 'high', wind: 'strong', play: false},
];

let tree = ID3.createTree(examples, 'play', example => example.play);
let label = tree.classify({outlook: 'sunny', humidity: 'high', wind: 'weak'});

API

ID3.createTree(dataset, targetAttribute, predicate) => Tree

Returns a Tree object created from the training dataset.

• dataset - object array. The training dataset for creating the tree.
• targetAttribute - string. The attribute of each item in the dataset which defines the class this test case belongs to.
• predicate - function (optional). Must be of the form example => boolean. If supplied, will be used to determine the class each case belongs to. This is helpful if the target attribute is continuous. If ommited, the default predicate will be used example => example[targetAttribute].

Tree.classify(case) => boolean

Returns a boolean indicating the label of the case according to the target attribute used when creating the tree.

• case - object. Must be similar to the objects used when creating the tree.