Java Collections swap()用法及代码示例

java.util.Collections类的swap()方法用于交换指定列表中指定位置的元素。如果指定位置相等，则调用此方法将使列表保持不变。

用法:

public static void swap(List list, int i, int j)

参数：此方法将以下参数作为参数

list –交换元素的列表。
i –要交换的一个元素的索引。
j –要交换的其他元素的索引。

异常如果i或j超出范围(i = list.size() || j = list.size())，则此方法引发IndexOutOfBoundsException。

以下示例说明了swap()方法

示例1:

// Java program to demonstrate 
// swap() method for String value 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
        throws Exception 
    { 
  
        try { 
  
            // creating object of List<String> 
            List<String> vector = new ArrayList<String>(); 
  
            // populate the vector 
            vector.add("A"); 
            vector.add("B"); 
            vector.add("C"); 
            vector.add("D"); 
            vector.add("E"); 
  
            // pritning the vector before swap 
            System.out.println("Before swap: " + vector); 
  
            // swap the elements 
            System.out.println("\nSwapping 0th and 4th element."); 
            Collections.swap(vector, 0, 4); 
  
            // priting the vector after swap 
            System.out.println("\nAfter swap: " + vector); 
        } 
  
        catch (IndexOutOfBoundsException e) { 
            System.out.println("\nException thrown : " + e); 
        } 
    } 
}

输出：

Before swap: [A, B, C, D, E]

Swapping 0th and 4th element.

After swap: [E, B, C, D, A]

示例2:对于IndexOutOfBoundsException

// Java program to demonstrate 
// swap() method for IndexOutOfBoundsException 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) throws Exception 
    { 
        try { 
  
            // creating object of List<String> 
            List<String> vector = new ArrayList<String>(); 
  
            // populate the vector 
            vector.add("A"); 
            vector.add("B"); 
            vector.add("C"); 
            vector.add("D"); 
            vector.add("E"); 
  
            // pritning the vector before swap 
            System.out.println("Before swap: " + vector); 
  
            // swap the elements 
            System.out.println("\nTrying to swap elements"
                               + " more than upper bound index "); 
            Collections.swap(vector, 0, 5); 
  
            // priting the vector after swap 
            System.out.println("After swap: " + vector); 
        } 
  
        catch (IndexOutOfBoundsException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

Before swap: [A, B, C, D, E]

Trying to swap elements more than upper bound index 
Exception thrown : java.lang.IndexOutOfBoundsException: Index: 5, Size: 5

相关用法

注：本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 Collections swap() method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。