What is ArrayUtils.removeAllOccurrences in java?

removeAllOccurrences is a static method of the ArrayUtils class that removes all the occurrences of an element in the given array. All the subsequent elements are shifted to the left in the array once all the occurrences are removed.

Example 1

  • Array = [1,2,3,2,4,5]
  • Element = 2

The array [1,3,4,5] is a result of applying the removeAllOccurrences function.

All occurrences of the element 2 are removed and the subsequent elements are shifted to the left in the array.

Example 2

  • Array = [1,2,3,2,4,5]
  • Element = -2

The array [1,2,3,2,4,5] is a result of applying the removeAllOccurrences function.

The array is returned as it is because the element is not found in the array.

ArrayUtils is defined in the Apache Commons Lang package. Apache Commons Lang can be added to the Maven project by adding the following dependency to the pom.xml file.

<dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.12.0</version>
</dependency>

For other versions of the commons-lang package, refer to the Maven Repository.

You can import the ArrayUtils class as follows:

import org.apache.commons.lang3.ArrayUtils;

Syntax

public static int[] removeAllOccurrences(final int[] array, final int element)

Parameters

  • final int[] array - the array from which the element has to be removed.
  • final int element - element to be removed.

Returns

  • The method returns a new array with all the occurrences of the element removed.

Code

import org.apache.commons.lang3.ArrayUtils;
public class Main {
    public static void main(String[] args) {
        int[] array = {1,2,3,4,5,4,2,3,2,4,5};
        System.out.print("Original Array - ");
        for(int i: array){
            System.out.print(i + " ");
        }
        int[] result = ArrayUtils.removeAllOccurrences(array, 4);
        System.out.print("\nModified Array after removing element 4 - ");
        for(int i: result){
            System.out.print(i + " ");
        }
    }
}

Expected Output

Original Array - 1 2 3 4 5 4 2 3 2 4 5 
Modified Array after removing element 4 - 1 2 3 5 2 3 2 5
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