Question

Solve Project 2 using a TreeMap. You can display the words in key sequence without performing a sort. Java

Project 2: Use a HashMap to store the frequency counts for all the words in a large text document. When you are done, display the contents of this HashMap. Next, create a set view of the Map and store its contents in an array. Then sort the array based on key value and display it. Finally, sort the array in decreasing order by frequency and display it.

Syntax for Project 2:

import java.util.*;
import java.io.*;


public class WordFrequencies {

    @SuppressWarnings({"unchecked"})
    public static void main(String[] args) throws Exception {
        String filename = "test.txt";
        Map<String,Integer> frequencies = new HashMap<String,Integer>();
        Scanner sc = new Scanner(new File(filename));
        while (sc.hasNext()) {
            String word = sc.next();
            if (frequencies.containsKey(word)) {
                // increment the frequency count for this word by 1
                frequencies.put(word,frequencies.get(word)+1);
            } else {
                // start the frequency count at 1
                frequencies.put(word,1);
            }
        }
               
        System.out.println(frequencies);
       
        Set<Map.Entry<String,Integer>> entries = frequencies.entrySet();
       
        // Store the contents of entries in an array of Map.Entry<String,Integer>
        // This will cause an unchecked conversion warning unless we suppress it
        Map.Entry<String,Integer> [] entryArray = entries.toArray(new Map.Entry[0]);
               
        Arrays.sort(entryArray, new Comparator<Map.Entry<String,Integer>>() {
            public int compare(Map.Entry<String,Integer> o1, Map.Entry<String,Integer> o2) {
                return o1.getKey().compareTo(o2.getKey());
            }
        });
       
        for (Map.Entry<String,Integer> entry : entryArray) System.out.println(entry);
       
        Arrays.sort(entryArray, new Comparator<Map.Entry<String,Integer>>() {
            public int compare(Map.Entry<String,Integer> o1, Map.Entry<String,Integer> o2) {
                return o1.getValue().compareTo(o2.getValue());
            }
        });
        for (Map.Entry<String,Integer> entry : entryArray) System.out.println(entry);
       
    }

}

Answer 1

import java.util.*;
import java.io.*;


public class WordFrequencies {

    @SuppressWarnings({"unchecked"})
    public static void main(String[] args) throws Exception {
        String filename = "test.txt";
        Map<String,Integer> frequencies = new HashMap<String,Integer>();
        Scanner sc = new Scanner(new File(filename));
        while (sc.hasNext()) {
            String word = sc.next();
            if (frequencies.containsKey(word)) {
                // increment the frequency count for this word by 1
                frequencies.put(word,frequencies.get(word)+1);
            } else {
                // start the frequency count at 1
                frequencies.put(word,1);
            }
        }
               
        System.out.println(frequencies);
       
        Set<Map.Entry<String,Integer>> entries = frequencies.entrySet();
       
        // Store the contents of entries in an array of Map.Entry<String,Integer>
        // This will cause an unchecked conversion warning unless we suppress it
        Map.Entry<String,Integer> [] entryArray = entries.toArray(new Map.Entry[0]);
               
        Arrays.sort(entryArray, new Comparator<Map.Entry<String,Integer>>() {
            public int compare(Map.Entry<String,Integer> o1, Map.Entry<String,Integer> o2) {
                return o1.getKey().compareTo(o2.getKey());
            }
        });
       
        for (Map.Entry<String,Integer> entry : entryArray) System.out.println(entry);
       
        Arrays.sort(entryArray, new Comparator<Map.Entry<String,Integer>>() {
            public int compare(Map.Entry<String,Integer> o1, Map.Entry<String,Integer> o2) {
                return o1.getValue().compareTo(o2.getValue());
            }
        });
        for (Map.Entry<String,Integer> entry : entryArray) System.out.println(entry);
       
    }

}