Syncronized sorting between two ArrayLists

Question

I have two ArrayLists.

• The first contains a group of words with capitalization and punctuation.

• The other contains this same group of words, but with the capitalization and punctuation removed.

.

ArrayList1 ..... ArrayList2

MURDER! ........ murder

It's ........... its

Hello .......... hello

Yes-Man ........ yesman

ON ............. on

The second array has all the words alphabetized and all the letters in each word alphabetized. It looks something like this:

aemnsy
demrru
ehllo
ist
no

I want to make it so that when I arrange the words in ArrayList two into alphabetical order, all the words from ArrayList one follow suite:

ArrayList1 ..... ArrayList2

Yes-Man ........ aemnsy

MURDER! ........ demrru

Hello .......... ehllo

It's ........... ist

ON ............. no

I tried to make a loop with a for statement or two, but it ended up not working and became very long. How do I do this? How do I do this efficiently?

Answer 1

Here is a function to sort multiple lists based on a single 'key' list. The lists do not need to be the same type, here the key list is type String and it's used to sort a String , Integer , and Double list ( Ideone Example ):

List<String> key = Arrays.asList("demrru", "ist", "ehllo", "aemnsy", "no");
List<String> list1 = Arrays.asList("MURDER!","It's", "Hello","Yes-Man", "ON");
List<Integer> list2 = Arrays.asList(2, 4, 3, 1, 5);            // Also use Integer type 
List<Double>  list3 = Arrays.asList(0.2, 0.4, 0.3, 0.1, 0.5);  // or Double type

// Sort all lists (excluding the key)
keySort(key, list1, list2, list3);

// Sort all lists (including the key)
keySort(key, key, list1, list2, list3);

Output:

// Sorted by key:
[Yes-Man, MURDER!, Hello, It's, ON]
[aemnsy, demrru, ehllo, ist, no]
[1, 2, 3, 4, 5]
[0.1, 0.2, 0.3, 0.4, 0.5]

---

Sort Function

An Ideone Example can be found here which includes validation of parameters and a test case.

public static <T extends Comparable<T>> void keySort(
                                        final List<T> key, List<?>... lists){
    // Create a List of indices
    List<Integer> indices = new ArrayList<Integer>();
    for(int i = 0; i < key.size(); i++)
        indices.add(i);

    // Sort the indices list based on the key
    Collections.sort(indices, new Comparator<Integer>(){
        @Override public int compare(Integer i, Integer j) {
            return key.get(i).compareTo(key.get(j));
        }
    });

    // Create a mapping that allows sorting of the List by N swaps.
    Map<Integer,Integer> swapMap = new HashMap<Integer, Integer>(indices.size());

    // Only swaps can be used b/c we cannot create a new List of type <?>
    for(int i = 0; i < indices.size(); i++){
        int k = indices.get(i);
        while(swapMap.containsKey(k))
            k = swapMap.get(k);

        swapMap.put(i, k);
    }

    // for each list, swap elements to sort according to key list
    for(Map.Entry<Integer, Integer> e : swapMap.entrySet())
        for(List<?> list : lists)
            Collections.swap(list, e.getKey(), e.getValue());
}

Answer 2

First Way - I use map whose key is from arrayList2 and value is from arrayList1. Putting data to map is up to you. After sorting arrayList2, I get its value from map.

  List<String> arrList1 = new ArrayList<String>();

            arrList1.add("MURDER!");
            arrList1.add("It's");
            arrList1.add("Hello");
            arrList1.add("Yes-Man");
            arrList1.add("ON");

            List<String> arrList2 = new ArrayList<String>();
            arrList2.add("demrru");
            arrList2.add("aemnsy");
            arrList2.add("ist");
            arrList2.add("ehllo");
            arrList2.add("no"); 

            Map<String, String> map1 = new HashMap<String, String>();
            map1.put("aemnsy", "Yes-Man");
            map1.put("demrru", "MURDER!");
            map1.put("ehllo", "Hello");
            map1.put("ist", "It's");
            map1.put("no", "ON");

            Collections.sort(arrList2);

            for (String s : arrList2){
                System.out.println(s + "..........." + map1.get(s));
            }

Second Way - Another way is you can use only TreeMap which is already sorted instead of two ArrayList.

Map<String, String> map2 = new TreeMap<String, String>();
            map2.put("ehllo", "Hello");
            map2.put("aemnsy", "Yes-Man");
            map2.put("demrru", "MURDER!");
            map2.put("no", "ON");
            map2.put("ist", "It's");

            for (Map.Entry<String, String> entry : map2.entrySet())
            {
                System.out.println(entry.getKey() + "/" + entry.getValue());
            }

Third way - only using 2 ArrayList, but we have to write sorting method by our own. Have you notice that your 2 ArrayList elements such as aemnsy from arrayList2 and Yes-Man from arrayList1 have same index? I use that point.

  selectionSort1(arrList2, arrList1);

    for(int i = 0; i < arrList1.size(); i++){
        System.out.println(arrList2.get(i) + "---" + arrList1.get(i));
    }

   public static void selectionSort1(List<String> x, List<String> y) {
    for (int i=0; i<x.size()-1; i++) {
        for (int j=i+1; j<x.size(); j++) {
            if (x.get(i).compareTo(x.get(j)) > 0) {
                //... Exchange elements in first array
                String temp = x.get(i);
                x.set(i, x.get(j));
                x.set(j, temp);

                //... Exchange elements in second array
                temp = y.get(i);
                y.set(i, y.get(j));
                y.set(j, temp);
            }
        }
    }
}

Answer 3

A Quick Answer.

public class MapAlph {
    public static void main(String[] args) {
        HashMap<String, String> map = new HashMap<String, String>();
        String txt = "Murde!r!";
        ArrayList<Character> alph = new ArrayList<Character>();
        for (int i = 0; i < txt.length(); i++)
            if (Character.isLetter(txt.charAt(i)))
                alph.add(txt.charAt(i));

        Collections.sort(alph);
        Collections.reverse(alph);
        String val = "";
        for (Character c : alph)
            val += c;

        map.put(txt, val);
        System.out.print(txt + " ........ " + map.get(txt));
    }
}

Answer 4

You can make use of TreeMap , if you wish.

Map<String, String> sortedMap = new TreeMap<String, String>();
sortedMap.put("demrru", "MURDER!");
sortedMap.put("ist", "It's");
sortedMap.put("aemnsy", "Yes-Man");
sortedMap.put("ehllo", "Hello");
sortedMap.put("no", "ON");

Answer 5

You can try this:

import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;


public class SortService {

    public static void main(String[] args) {
        Map<String, String> originalMap = new HashMap<String, String>();
        originalMap.put("aemnsy", "Yes-Man");
        originalMap.put("demrru", "MURDER!");
        originalMap.put("ehllo", "Hello");
        originalMap.put("ist", "It's");
        originalMap.put("no", "ON");

        Map<String, String> sortedMap = new TreeMap<String, String>(originalMap);
        System.out.println(sortedMap);
    }

}

output:

{aemnsy=Yes-Man, demrru=MURDER!, ehllo=Hello, ist=It's, no=ON}