How to Remove Duplicates in an Array in Java - Step by Step Examples

How to Remove Duplicates in an Array in Java ?

Answer

To remove duplicates in an array in Java, you can use the HashSet class or manually iterate through the array to filter duplicates.

✐ Examples

1 Remove Duplicates Using HashSet

In this example,

We create an array named array with duplicate elements.
We create a HashSet named set and add all elements of the array to it.
HashSet automatically removes duplicates.
We convert the HashSet back to an array if necessary.
We print the new array or HashSet to demonstrate the removal of duplicates.

Java Program

import java.util.*;
public class Main {
    public static void main(String[] args) {
        Integer[] array = {1, 2, 2, 3, 4, 4, 5};
        Set<Integer> set = new HashSet<>(Arrays.asList(array));
        System.out.println(set);
    }
}

Output

[1, 2, 3, 4, 5]

2 Remove Duplicates Using Manual Iteration

In this example,

We create an array named array with duplicate elements.
We create an empty ArrayList named result to store unique elements.
We iterate through the array and add elements to result only if they are not already present.
We convert result back to an array if necessary.
We print the new array or ArrayList to demonstrate the removal of duplicates.

Java Program

import java.util.*;
public class Main {
    public static void main(String[] args) {
        Integer[] array = {1, 2, 2, 3, 4, 4, 5};
        List<Integer> result = new ArrayList<>();
        for (Integer element : array) {
            if (!result.contains(element)) {
                result.add(element);
            }
        }
        System.out.println(result);
    }
}

Output

[1, 2, 3, 4, 5]

Summary

In this tutorial, we learned How to Remove Duplicates in an Array in Java language with well detailed examples.

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How to Remove Duplicates in an Array in Java - Step by Step Examples

How to Remove Duplicates in an Array in Java ?

Answer

✐ Examples

1 Remove Duplicates Using HashSet

Java Program

Output

2 Remove Duplicates Using Manual Iteration

Java Program

Output

Summary

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