Thread: How to create a function that returns a new array containing duplicate values of another array?

I'm trying to do a problem that returns a new double array containing unique values from another double array (basically the new array will remove/delete duplicate numbers in the original array). I cannot use HashSets or ArrayLists in this problem. I tried using a brunt force method of swapping indexes from the original array and the new array I made. However, when there is only one element in an array, the function does not work. Below is my code. Example results, if this function is correct, include: new double [ ] {11, 22, 33, 44, 55, 66, 77, 88} < --removeDuplicates double [ ] {11, 11, 11, 11, 22, 33, 44, 44, 44, 44, 44, 55, 55, 66, 77, 88, 88}).

public static double[] removeDuplicates (double[] list) {
 
		int count = list.length - numDuplicates(list);
		double [ ] newList = new double[count]; //numDuplicates returns the number of duplicated values in an array
		int j = 0;
 
		for (int i = 0; i < list.length - 1; i++) {
			if (list[i] != list[i +1]) {
				newList[j++] = list[i];
			}
			newList[j] = list[list.length - 1];
		}
		return newList;
	}

1. Select next item from the list and add it to the new list.

2. Now get next item and see if it is in new list.
3. If no, add it
4. if yes ignore,
5. go back to 2 and repeat until done.

Regards,
Jim

Originally Posted by veretimothy

en.verejava.com/?id=19932689743040

package com.tool.util;
 
public class RemoveDuplicate {
 
    public static void main(String[] args) {
 
        double[] numArray = { 11, 11, 11, 11, 22, 33, 44, 44, 44, 44, 44, 55, 55, 66, 77, 88, 88 };
 
        double[] newArray = removeDuplicate(numArray);
 
        for (int i=0; i < newArray.length; i++) {
            System.out.print(newArray[i]+", ");
        }
 
    }
 
    public static double[] removeDuplicate(double[] arr) {
        int t = 0;
        double[] tempArr = new double[arr.length];
 
        for (int i = 0; i < arr.length; i++) {
            boolean isTrue = true;
            for (int j = i + 1; j < arr.length; j++) {
                if (arr[i] == arr[j]) {
                    isTrue = false;
                    break;
                }
            }
 
            if (isTrue) {
                tempArr[t] = arr[i];
                t++;
            }
        }
 
        double[] newArr = new double[t];
        System.arraycopy(tempArr, 0, newArr, 0, t);
        return newArr;
    }
}

This works but do you want doubles as a result or integers?


Cheers.