FeatureWeightCalculator.java

package edu.illinois.cs.cogcomp.tutorial;

import edu.illinois.cs.cogcomp.lbjava.learn.Lexicon;
import edu.illinois.cs.cogcomp.lbjava.learn.SparseNetworkLearner;

import java.io.ByteArrayOutputStream;
import java.io.PrintStream;
import java.util.*;
import java.util.stream.Stream;

public class FeatureWeightCalculator {


	public static <K, V extends Comparable<? super V>> Map<K, V> sortByValue( Map<K, V> map )
	{
		Map<K,V> result = new LinkedHashMap<>();
		Stream<Map.Entry<K,V>> st = map.entrySet().stream();

		st.sorted(Comparator.comparing(e -> e.getValue()))
				.forEach(e -> result.put(e.getKey(), e.getValue()));

		return result;
	}

	public static Map<String, Map<String, Double>> getFeatureWeights(SparseNetworkLearner c) {
		ByteArrayOutputStream sout = new ByteArrayOutputStream();
		c.write(new PrintStream(sout));
		String s = sout.toString();

		String[] lines = s.split("\n");

		Lexicon lexicon = c.getLexicon();

		// this maps a label to a hashmap of features.
		Map<String, Map<String, Double>> featslist = new HashMap<>();

		int i = 0;
		while(true) {

			if(lines[i].startsWith("label")){
				String label = lines[i].split(":")[1].trim();

				// skip two lines, and then read.
				i += 3;

				Map<String, Double> feats = new HashMap<>();
				for(int k = i; k < i + lexicon.size(); k++) {
					String line = lines[k];
					String featid = lexicon.lookupKey(k - i).toStringNoPackage(); // .getStringIdentifier();
					feats.put(featid, Double.parseDouble(line));
				}

				featslist.put(label, feats);

				i += lexicon.size();
			}

			i++;

			if(i >= lines.length){
				break;
			}
		}

		return featslist;
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		CsvSentimentClassifier bc = new CsvSentimentClassifier();

		Map<String, Map<String, Double>> maps = getFeatureWeights(bc);
		for(String k : maps.keySet()){
			Map m = maps.get(k);
			maps.put(k, sortByValue(m));
		}

		Map target = maps.get("Neutral");

		Object[] sarray = target.keySet().toArray();

		int topk = 10;

		for(int i = 0; i < topk; i++){
			System.out.println(sarray[i]);
			System.out.println(target.get(sarray[i]));
		}

		System.out.println();

		for(int i = sarray.length-1; i > sarray.length - topk; i--){
			System.out.println(sarray[i]);
			System.out.println(target.get(sarray[i]));
		}

	}

}