Guava Chars.indexOf()方法与实例

Guava的Chars类的Chars.indexOf(char[] array, char[] target)方法接受两个参数 array and target 。如果目标存在于数组中，该方法返回其第一次出现的起始位置。如果目标不存在于数组中，该方法返回 -1 .

语法:

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

参数: ** 该方法接受两个参数。

• array: ，这是一个整数数组，目标数组将在其中检查索引。
• target: 这是要作为指定数组的子序列进行搜索的数组。

返回值： 该方法返回一个整数值，如下所示。

• 如果目标数组在数组中存在，它返回目标数组第一次出现的起始位置。
• 否则，如果目标数组中不存在，则返回-1。

异常情况: 该方法不抛出任何异常。

下面的例子说明了上述方法的实现。

示例1:

// Java code to show implementation of
// Guava's Chars.indexOf(char[] array,
// char[] target) method
  
import com.google.common.primitives.Chars;
import java.util.Arrays;
  
class GFG {
  
    // Driver's code
    public static void main(String[] args)
    {
  
        // Creating an char array
        char[] arr = { 'G', 'F', 'G', 'E', 'E' };
  
        char[] target = { 'E', 'E' };
  
        System.out.println("Array: "
                           + Arrays.toString(arr));
  
        System.out.println("Target Array: "
                           + Arrays.toString(target));
  
        // Using Chars.indexOf(char[] array, char[] target)
        // method to get the start position of the first
        // occurrence of the specified target within array,
        // or -1 if there is no such occurrence.
        int index = Chars.indexOf(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:

Array: [G, F, G, E, E]
Target Array: [E, E]
Target is present at index 3

示例2:

// Java code to show implementation of
// Guava's Chars.indexOf(char[] array,
// char[] target) method
  
import com.google.common.primitives.Chars;
import java.util.Arrays;
  
class GFG {
  
    // Driver's code
    public static void main(String[] args)
    {
  
        // Creating an char array
        char[] arr = { 'H', 'E', 'L', 'L', 'O' };
  
        char[] target = { 'G', 'E', 'E' };
  
        System.out.println("Array: "
                           + Arrays.toString(arr));
  
        System.out.println("Target Array: "
                           + Arrays.toString(target));
  
        // Using Chars.indexOf(char[] array, char[] target)
        // method to get the start position of the first
        // occurrence of the specified target within array,
        // or -1 if there is no such occurrence.
        int index = Chars.indexOf(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:

Array: [H, E, L, L, O]
Target Array: [G, E, E]
Target is not present in the array

参考: https://google.github.io/guava/releases/23.0/api/docs/com/google/common/primitives/Chars.html#indexOf-char:A-char:A-