Duplicates

[Gambit17]

hey,

How do you remove duplicates in an array and the shift the whole array down so you dont have empty blanks in your array?
Thanks

[hardwired]

Code:

import java.util.Random;

public class ArrayResizing {
    public static void main(String[] args) {
        Random seed = new Random();
        int[] domain = new int[12];
        for(int j = 0; j < domain.length; j++)
            domain[j] = seed.nextInt(101);
        print(domain, "initial");
        for(int j = 0; j < 3; j++) {
            int index = seed.nextInt(domain.length);
            domain = removeElement(domain, index);
            print(domain, "remove element at " + index);
        }
    }

    private static int[] removeElement(int[] array, int index) {
        int n = array.length;
        int[] smaller = new int[n-1];
        for(int j = 0, k = 0; j < n; j++) {
            if(j == index)  // skip element at index
                continue;
            smaller[k++] = array[j];
        }
        return smaller;
    }

    private static void print(int[] array, String s) {
        System.out.println(s + ":");
        for(int j = 0; j < array.length; j++) {
            System.out.print(array[j]);
            if(j < array.length-1)
                System.out.print(", ");
        }
        System.out.println();
    }
}

[JavaBean]

You can traverse your array and recreate it. But temporarily you can keep the accepted elements inside a dynamic data structure like Vector since you will not know the size of the array until traversing is finished.

[bar311]

If you're array contains non-primitive data, try adding the elements using Set...

for example:

import java.util.*;

Code:

public class Duplicate {

	public static void main(String[] args) {
		String[] s = {"1","2","2","2","2","3","3","4"};
		s=removeDups(s);
		System.out.println(Arrays.asList(s));
	}
	
	public static String[] removeDups(String[] s){
		Set unique = new HashSet();
		for(int i=0; i<s.length; i++) unique.add(s[i]);
		System.out.println(unique);
		return (String[])unique.toArray(new String[0]);
	}
}

hope this one gives you an idea too. THanks =)

[Gambit17]

Thanks guys after like 5 hours i managed to do it like so:

Code:

	void removeDuplicates()
	{
		String[][] dupTemp = new String[100][4];
		for(int a = 1; a < songNum;a++)
		{
			for(int b = a + 1; b < songNum + 1; b++)
			{
				if(song[a][0].equals(song[b][0]) && song[a][1].equals(song[b][1]) && song[a][2].equals(song[b][2]) && song[a][3].equals(song[b][3]))
				{
						song[b][0]=" ";
						song[b][1]=" ";
						song[b][2]=" ";
						song[b][3]=" ";					
				}
			}//for b
		}//for a
		int size=0;
		for(int i = 1; i <= songNum; i++)
		{
			if(song[i][0].equals(" ")) size++;
			else dupTemp[i - size]=song[i];
		}//for						
		songNum -= size;
		for(int i = 1; i <= songNum ; i++) song[i] = dupTemp[i];	
	}//duplicates

ya that works, do you know of an easier way tho

[bar311]

Code:

public class Duplicate {

	public static void main(String[] args) {
		String[] s = {"2","2","4","1","2","2","3","3"};
		s=removeDups(s);
		System.out.println(Arrays.asList(s));
	}
	
	public static String[] removeDups(String[] s){
		List unique = new ArrayList();
		for(int i=0; i<s.length; i++){
			if(!unique.contains(s[i]))unique.add(s[i]);
		}
		return (String[])unique.toArray(new String[0]);
	}
}