Guava – Longs.lastIndexOf()方法与实例

The lastIndexOf() method of Guava库中的Longs类 ，用于查找长数组中给定长值的最后索引。这个要搜索的长值和要搜索的长数组，都作为参数传给这个方法。它返回一个整数，这个整数是指定长值的最后索引。如果没有找到该值，它返回-1。

语法:

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

参数: 这个方法接受两个强制性参数。

array: 这是一个长值数组，长值将在其中被搜索。
target:它是长数组中最后一个索引要搜索的长值。

返回值： 该方法返回一个整数值，即指定的长值的最后索引。如果没有找到该值，则返回-1。

下面的程序说明了这个方法。

示例1:

// Java code to show implementation of
// Guava's Longs.lastIndexOf() method
  
import com.google.common.primitives.Longs;
import java.util.Arrays;
  
class GFG {
  
    // Driver's code
    public static void main(String[] args)
    {
  
        // Creating a long array
        long[] arr = { 1, 2, 3, 4, 3, 5, 3, 4 };
  
        long target = 3;
  
        // Using Longs.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
            = Longs.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");
        }
    }
}

输出:

Target is present at index 6

示例2:

// Java code to show implementation of
// Guava's Longs.lastIndexOf() method
  
import com.google.common.primitives.Longs;
import java.util.Arrays;
  
class GFG {
  
    // Driver's code
    public static void main(String[] args)
    {
        // Creating a long array
        long[] arr = { 3, 5, 7, 11, 13 };
  
        long target = 17;
  
        // Using Longs.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
            = Longs.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");
        }
    }
}

输出: