Java Collection Examples : How To Remove Duplicate Elements From An Array

Intro

This examples will demonstrates how to remove duplicate elements from an array. To get it, you have to convert an array into a Set collection first.

Examples

package com.freesamplecode.java.array;

import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class RemoveDuplicateElementDemo {
	public static void main(String[] args){
		
		   // Step 1:  Prepare a duplicate array
		   String[] strArray = { "A", "B", "B", "C", "A", "D", "B", "A", "B", "D" };
		   
		   System.out.println("Original Array : "+Arrays.toString(strArray));
		   
		   // Step 2 : Convert an array to list
		   List list = Arrays.asList(strArray);
		   
		   // Step 3 : Create a Set object from list
		   Set set = new HashSet(list);
		   
		   // Step 4 : Create an array object to hold values from set
		   String[] newArray = new String[set.size()];
		   
		   // Step 5 : Convert a Set into an Array
		   set.toArray(newArray);
		   
		   // Step 6 : Display value after removing duplicate to console
		   System.out.print("After removing duplicates: "+Arrays.toString(newArray));
		   
		   
		   
	}
}

Output

Original Array : [A, B, B, C, A, D, B, A, B, D]
After removing duplicates: [D, A, B, C]

Screenshot

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