Java Guava | Chars.lastIndexOf() method with Examples

Last Updated : 31 Jan, 2019

The lastIndexOf() method of Chars Class in Guava library is used to find the last index of the given char value in a char array. This char value to be searched and the char 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 char value. If the value is not found, it returns -1.

Syntax:

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

Parameters: This method accepts two mandatory parameters:

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

Return Value: This method returns an integer value which is the last index of the specified char 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 Chars.lastIndexOf() method
  
import com.google.common.primitives.Chars;
import java.util.Arrays;
  
class GFG {
  
    // Driver's code
    public static void main(String[] args)
    {
  
        // Creating a char array
        char[] arr = { 'a', 'b', 'c', 'd',
                       'b', 'c', 'b', 'd' };
  
        char target = 'b';
  
        // Using Chars.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
            = Chars.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 Chars.lastIndexOf() method
  
import com.google.common.primitives.Chars;
import java.util.Arrays;
  
class GFG {
  
    // Driver's code
    public static void main(String[] args)
    {
        // Creating a char array
        char[] arr = { 'a', 'b', 'c', 'd',
                       'b', 'c', 'b', 'd' };
  
        char target = 'z';
  
        // Using Chars.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
            = Chars.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/18.0/api/docs/com/google/common/primitives/Chars.html#lastIndexOf(char[], %20char)

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