Remove Duplicate row from 2D integer array

Question

I know this question is asked before but I am really not able to find a working method I tried the method in the following link How to construct ArrayList from 2D int array? which I think is the most relevant to my case I applied the following code:

import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
public class MonteCarloSim {

    private int[] ints;

    public MonteCarloSim(int[] ints) {
        this.ints = ints.clone();
        Arrays.sort(this.ints);
    }

    @Override
    public int hashCode() {
        return Arrays.hashCode(ints);
    }

    @Override
    public boolean equals(Object obj) {

        if(obj instanceof MonteCarloSim) {
            MonteCarloSim another = (MonteCarloSim) obj;
            int[] original = Arrays.copyOf(another.ints, another.ints.length);
            return Arrays.equals(ints, original);
        } else {
            return false;
        }
    }

    @Override
    public String toString() {
        return Arrays.toString(ints);
    }

    public static void main(String arg[]){

then I determined a 2D integer array with zero, one elements having a size of 1000*20 called IncProb1 I apply the following code to remove dublicate rows:

int[][] arrays = IncProb1;
        Set<MonteCarloSim> rows = new HashSet<MonteCarloSim>();
        for(int[] a: arrays) {
            rows.add(new MonteCarloSim(a));
        }
        for(MonteCarloSim row: rows) {
            System.out.println(row);
        }

But this doesn't work I only get one row which is [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1] and this is not the solution there should be at least 300 rows not repeated. I don't know whats wrong Any help is highly appreciated Thanks in advance

theJango · Accepted Answer · 2015-01-02 06:40:53Z

0

Following method will solve your problem

public static int[][] removeDuplicateRow(int[][] testArr)
    {
        /**
         * This method will remove the duplicate ROW from 2-D array and replace with {0,0,0}
         * However i assume array rows  =5 and coloums =3 ;) You can have the solution for that I assume
         */

        HashSet<String> hashSet = new HashSet<String>();
        int[][] result = new int[5][3];
        int i = 0;
        for(int[] a : testArr)
        {
            System.out.println(Arrays.toString(a));
            System.out.println(hashSet.contains(a));
            if(!hashSet.contains(Arrays.toString(a))){
                hashSet.add(Arrays.toString(a));
                result[i] = a;
            }
            i++;
        }

        System.out.println("old array : "+Arrays.deepToString(testArr));
        System.out.println("new array : "+Arrays.deepToString(result));

        return result;
    }

Hope this helps.

answered Jan 2, 2015 at 6:40

theJango

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5 Comments

Ahmad Ghazi Altarabsheh Over a year ago

Thanks but how I can convert the array back to double?

theJango Over a year ago

@AhmadGhaziAltarabsheh I didn't get you what you mean by 'double'. As this method returns an 2-D integer Array, you can use it to any primitive type, you need to change the array type only.

Ahmad Ghazi Altarabsheh Over a year ago

Sorry I mean how I can convert the resulting array to 2D integer array

Ahmad Ghazi Altarabsheh Over a year ago

Also How I can delet the zero rows

theJango Over a year ago

Returning array is a 2-D array itself. You can copy the returning array to a new array with some logic for example on the basis of sum of all the elements in a row, if sum >0 then row will be added sum =0 , then not.

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