在Java中交换列表的项目:Collections.swap() 与示例
Java.util.Collections.swap()方法是一个Java.util.Collections 类方法。它交换给定列表中指定位置的元素。
// Swaps elements at positions "i" and "j" in myList.
public static void swap(List mylist, int i, int j)
It throws IndexOutOfBoundsException if either i
or j is out of range.
// Java program to demonstrate working of Collections.swap
import java.util.*;
public class GFG
{
public static void main(String[] args)
{
// Let us create a list with 4 items
ArrayList mylist =
new ArrayList();
mylist.add("code");
mylist.add("practice");
mylist.add("quiz");
mylist.add("geeksforgeeks");
System.out.println("Original List : \n" + mylist);
// Swap items at indexes 1 and 2
Collections.swap(mylist, 1, 2);
System.out.println("\nAfter swap(mylist, 1, 2) : \n"
+ mylist);
// Swap items at indexes 1 and 3
Collections.swap(mylist, 3, 1);
System.out.println("\nAfter swap(mylist, 3, 1) : \n"
+ mylist);
}
}
输出:
Original List : Original List :
[code, practice, quiz, geeksforgeeks]
After swap(mylist, 1, 2) :
[code, quiz, practice, geeksforgeeks]
After swap(mylist, 3, 1) :
[code, geeksforgeeks, practice, quiz]