Sorting two arrays simultaneously

Question

I\'m learning and understanding Java now, and while practising with arrays I had a doubt. I wrote the following code as an example:

Answer 1

What you want is not possible because you don't know internally how Arrays.sort swap the elements in your String array, so there is no way to swap accordingly the elements in the int array.

You should create a class that contains the String name and the int position as parameter and then sort this class only with the name, providing a custom comparator to Arrays.sort.

If you want to keep your current code (with 2 arrays, but this not the ideal solution), don't use Arrays.sort and implement your own sorting algorithm. When you swap two names, get the index of them and swap the two integers in the other array accordingly.

Answer 2

You should not have two parallel arrays. Instead, you should have a single array of WestWingCharacter objects, where each object would have a field name and a field number.

Sorting this array by number of by name would then be a piece of cake:

Collections.sort(characters, new Comparator<WestWingCharacter>() {
    @Override
    public int compare(WestWingCharacter c1, WestWingCharacter c2) {
        return c1.getName().compareTo(c2.getName();
    }
});

or, with Java 8:

Collections.sort(characters, Comparator.comparing(WestWingCharacter::getName));

Java is an OO language, and you should thus use objects.

Answer 3

Below is the code without using any Map Collection, but if you want to use Map then it becomes very easy. Add both the arrays into map and sort it.

public static void main(String args[]) {
    String a[] = new String[] {
        "Sam", "Claudia", "Josh", "Toby", "Donna"
    };
    int b[] = new int[] {
        1, 2, 3, 4, 5
    };
    for (int n = 0; n < 5; n++) {
        System.out.print(a[n] + "...");
        System.out.println(b[n]);
    }
    System.out.println(" ");
    //java.util.Arrays.sort(a);
    /* Bubble Sort */
    for (int n = 0; n < 5; n++) {
        for (int m = 0; m < 4 - n; m++) {
            if ((a[m].compareTo(a[m + 1])) > 0) {
                String swapString = a[m];
                a[m] = a[m + 1];
                a[m + 1] = swapString;
                int swapInt = b[m];
                b[m] = b[m + 1];
                b[m + 1] = swapInt;
            }
        }
    }
    for (int n = 0; n < 5; n++) {
        System.out.print(a[n] + "...");
        System.out.println(b[n]);
    }
}

Answer 4

You have to ZIP your two arrays into an array which elements are instances of a class like:

class NameNumber 
{

    public NameNumber(String name, int n) {
        this.name = name;
        this.number = n;
    }

    public String name;
    public int number;
}  

And sort that array with a custom comparator.

Your code should be something like:

NameNumber [] zip = new NameNumber[Math.min(a.length,b.length)];
for(int i = 0; i < zip.length; i++)
{
    zip[i] = new NameNumber(a[i],b[i]);
}

Arrays.sort(zip, new Comparator<NameNumber>() {

    @Override
    public int compare(NameNumber o1, NameNumber o2) {
        return Integer.compare(o1.number, o2.number);
    }
});

Answer 5

Here is the answer for your query.

public class Main {
  public static void main(String args[]){

  String name[] = new String[] {"Sam", "Claudia", "Josh", "Toby", "Donna"};
        int id[] = new int[] {1, 2, 3, 4, 5};

        for ( int i = 0; i < n; i++) {
            for (int j = i + 1; j < n; j++) {
                int dtmp=0;
                String stmp=null;
                if (id[i] > id[j]) {
                    dtmp = rate[i];
                    id[i] = id[j];
                    id[j] = dtmp;
                    stmp = name[i];
                    name[i]=name[j];
                    name[j]=stmp;
                }
            }
        }
        System.out.println("Details are :");
        for(int i=0;i<n;i++){
            System.out.println(name[i]+" - "+id[i]);
        }
    }
}

Answer 6

   import java.util.*;

class mergeArrays2
{
  public static void main(String args[])
  {
     String a1[]={"Sam", "Claudia", "Josh", "Toby", "Donna"};
     Integer a2[]={11, 2, 31, 24, 5};

     ArrayList ar1=new ArrayList(Arrays.asList(a1));

     Collections.sort(ar1);

     ArrayList ar2=new ArrayList(Arrays.asList(a2));

     Collections.sort(ar2);





     System.out.println("array list"+ar1+ " "+ar2);
  }

}