How do I find specific elements or object in an array?

By Wayan in Apache Commons, Commons Lang 0 Comment

This example demonstrates how to find specific items in an array. We will use the org.apache.commons.lang3.ArrayUtils class. This class provides method called contains(Object[] array, Object objectToFind) method to check if an array contains the objectToFind in it.

We can also use the indexOf(Object[] array, Object objectToFind) method and the lastIndexOf(Object[] array, Object objectToFind) method to get the index of an array element where our objectToFind is located.

package org.kodejava.commons.lang;

import org.apache.commons.lang3.ArrayUtils;

public class ArrayUtilsIndexOfDemo {
    public static void main(String[] args) {
        String[] colors = { "Red", "Orange", "Yellow", "Green",
                "Blue", "Violet", "Orange", "Blue" };

        // Does the "colors" array contain the Blue color?
        boolean contains = ArrayUtils.contains(colors, "Blue");
        System.out.println("Contains Blue? " + contains);

        // Can you tell me the index of each color defined bellow?
        int indexOfYellow = ArrayUtils.indexOf(colors, "Yellow");
        System.out.println("indexOfYellow = " + indexOfYellow);

        int indexOfOrange = ArrayUtils.indexOf(colors, "Orange");
        System.out.println("indexOfOrange = " + indexOfOrange);

        int lastIndexOfOrange = ArrayUtils.lastIndexOf(colors, "Orange");
        System.out.println("lastIndexOfOrange = " + lastIndexOfOrange);
    }
}

Here are the results of the code above.

Contains Blue? true
indexOfYellow = 2
indexOfOrange = 1
lastIndexOfOrange = 6

Maven Dependencies

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.14.0</version>
</dependency>

Maven Central

Wayan
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