How do I find specific elements in an array?

This example demonstrate how to find specific items in array. We use the org.apache.commons.lang.ArrayUtils class. This class provides method such as contains(Object[] array, Object objectToFind) to check if the array contains some value. We can also use the indexOf(Object[] array, Object objectToFind) and lastIndexOf(Object[] array, Object objectToFind) methods to gen the index of array where our object is located.

package org.kodejava.example.commons.lang;

import org.apache.commons.lang.ArrayUtils;

public class ArrayUtilsIndexOf {
    public static void main(String[] args) {
        String[] colours = { "Red", "Orange", "Yellow", "Green"
                , "Blue", "Violet", "Orange", "Blue" };
        
        /*
         * Does colours array contains the Blue colour? 
         */
        boolean contains = ArrayUtils.contains(colours, "Blue");        
        System.out.println("Contains Blue? " + contains);
        
        /*
         * Can you tell me the index of each colour defined bellow? 
         */
        int indexOfYellow = ArrayUtils.indexOf(colours, "Yellow");
        System.out.println("indexOfYellow = " + indexOfYellow);

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

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

Here are the result of the code above.

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

Wayan Saryada

Programmer, runner, recreational diver, currently living in the island of Bali, Indonesia. Mostly programming in Java, creating web based application with Spring Framework, Hibernate / JPA.

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