Java Guava | Bytes.lastIndexOf() method with Examples

Last Updated : 31 Jan, 2019

The lastIndexOf() method of Bytes Class in Guava library is used to find the last index of the given byte value in a byte array. This byte value to be searched and the byte array in which it is to be searched, both are passed as a parameter to this method. It returns an integer value which is the last index of the specified byte value. If the value is not found, it returns -1.

Syntax:

public static int lastIndexOf(byte[] array,
                              byte target)

Parameters: This method accepts two mandatory parameters:

array: which is the array of byte values in which the byte value is to searched.
target: which is byte value to be searched for last index in the byte array.

Return Value: This method returns an integer value which is the last index of the specified byte value. If the value is not found, it returns -1.

Below programs illustrates this method:

Example 1:

// Java code to show implementation of 
// Guava's Bytes.lastIndexOf() method 
  
import com.google.common.primitives.Bytes; 
import java.util.Arrays; 
  
class GFG { 
  
    // Driver's code 
    public static void main(String[] args) 
    { 
  
        // Creating a byte array 
        byte[] arr = { 1, 2, 3, 4, 3, 5, 3, 4 }; 
  
        byte target = 3; 
  
        // Using Bytes.lastIndexOf() method 
        // to get the index of last appearance 
        // of a given element in array 
        // and return -1 if element is 
        // not found in the array 
        int index 
            = Bytes.lastIndexOf(arr, target); 
  
        if (index != -1) { 
            System.out.println("Target is present"
                               + " at index "
                               + index); 
        } 
        else { 
            System.out.println("Target is not present"
                               + " in the array"); 
        } 
    } 
} 

Output:

Target is present at index 6

Example 2:

// Java code to show implementation of 
// Guava's Bytes.lastIndexOf() method 
  
import com.google.common.primitives.Bytes; 
import java.util.Arrays; 
  
class GFG { 
  
    // Driver's code 
    public static void main(String[] args) 
    { 
        // Creating a byte array 
        byte[] arr = { 3, 5, 7, 11, 13 }; 
  
        byte target = 17; 
  
        // Using Bytes.lastIndexOf() method 
        // to get the index of last appearance 
        // of a given element in array 
        // and return -1 if element is 
        // not found in the array 
        int index 
            = Bytes.lastIndexOf(arr, target); 
  
        if (index != -1) { 
            System.out.println("Target is present"
                               + " at index "
                               + index); 
        } 
        else { 
            System.out.println("Target is not present"
                               + " in the array"); 
        } 
    } 
} 

Output:

Target is not present in the array

Reference: https://google.github.io/guava/releases/19.0/api/docs/com/google/common/primitives/Bytes.html#lastIndexOf(byte[], %20byte)

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