CODEWITHSUNDEEP
javaarrayssortingdouble
Megan
Megan

Reputation: 1

Sorting an array of objects by two doubles

So I had a delimited file that I read into an array.

array[0] is the boxID (double)

and

array[1] is the movieID (double)

I have no clue how I'd be able to sort my array by these two doubles. Any comments? I've tried looking at other questions on this website but I just got confused by them. I'm currently in my first programming class.

Movies[] newMasterMovies = new Movies[200];

    int newMasterCount = 0;
    int masterCount = 0;
    int updateCount = 0;

    while (updateCount < updateTotalCounter || masterCount < masterTotalCounter) {

        String updateCompare = updateMovies[updateCount].getBoxID() + updateMovies[updateCount].getMovieID();
        String masterCompare = masterMovies[masterCount].getBoxID() + masterMovies[masterCount].getMovieID();
        int compare = updateCompare.compareTo(masterCompare);

        if (compare > 0) {
            newMasterMovies[newMasterCount] = masterMovies[masterCount];
            masterCount++;
            newMasterCount++;
        }

        if (updateMovies[updateCount].getActionCode() == "A") {
            newMasterMovies[newMasterCount] = updateMovies[updateCount];
            updateCount++;
            newMasterCount++;
        }

        if (updateMovies[updateCount].getActionCode() == "D") {
            updateCount++;
            masterCount++;
        }

        if (updateMovies[updateCount].getActionCode() == "C") {
            newMasterMovies[newMasterCount] = updateMovies[updateCount];
            updateCount++;
            newMasterCount++;
            masterCount++;
        }

    }

That is what my array looks like that I am trying to sort. I tried to do a selection sort but got confused since I want to sort by two properties, not just one.

Upvotes: 0

Views: 79

Answers (2)

magooup
magooup

Reputation: 134

To simply sort your Movies[] you can use Arrays.sort and use a custom Comparator. Like this:

    Arrays.sort(masterMovies, new Comparator<Movies>() {
        @Override
        public int compare(Movies o1, Movies o2) {
            // compare boxID
            // compare movieID
            return 0; // return result
        }
    });

Arrays.sort use merge sort or binary insertion sort which are both more stable and faster than selection sort.

If you insist to do your selection sort, try to edit yor class Movies to implement Comparable interface, like this: class Movies implements Comparable<Movies>. And implement compareTo method like this:

    @Override
    public int compareTo(Movies o) {
        // compare boxID
        // compare movieID
        return 0; // return result
    }

And change your old compare code int compare = updateCompare.compareTo(masterCompare); to int compare=updateMovies[updateCount].compareTo(masterMovies[masterCount]);, then go on.

Upvotes: 0

MNM
MNM

Reputation: 2743

This guy here does a wonders

  Arrays.sort(iArr);

Here is what it can do: Here is an example code

 public class ArrayDemo {

 public static void main(String[] args) {

     // initializing unsorted int array
     int iArr[] = {2, 1, 9, 6, 4};

     // let us print all the elements available in list
     for (int number : iArr) {
     System.out.println("Number = " + number);
     }

     // sorting array
     Arrays.sort(iArr);

     // let us print all the elements available in list
     System.out.println("The sorted int array is:");
     for (int number : iArr) {
     System.out.println("Number = " + number);
    }
  }
}

And the results should be like this

Number = 2

Number = 1

Number = 9

Number = 6

Number = 4

The sorted int array is:

Number = 1

Number = 2

Number = 4

Number = 6

Number = 9

Hopes this helps some

Upvotes: 1

Related Questions