Java 示例 - 反转数组列表

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  问题描述

  如何反转数组列表？
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  解决方案

  以下示例使用 Collections.reverse(ArrayList) 方法反转数组列表。

  
  import java.util.ArrayList;
  import java.util.Collections;
  public class Main {
     public static void main(String[] args) {
        ArrayList arrayList = new ArrayList();
        arrayList.add("A");
        arrayList.add("B");
        arrayList.add("C");
        arrayList.add("D");
        arrayList.add("E");
        System.out.println("Before Reverse Order: " + arrayList);
        Collections.reverse(arrayList);
        System.out.println("After Reverse Order: " + arrayList);
     }
  }
  

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  结果

  上面的代码示例将产生以下结果。

  
  Before Reverse Order: [A, B, C, D, E]
  After Reverse Order: [E, D, C, B, A]
  

  下面的例子是数组反转的另一个例子。

  
  public class HelloWorld {
     public static void main(String[] args) {
        int[] numbers = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
        System.out.println("Array before reverse:");
        
        for (int i = 0; i < numbers.length; i++) {
           System.out.print(numbers[i] + " ");
        } 
        for (int i = 0; i < numbers.length / 2; i++) {
           int temp = numbers[i];
           numbers[i] = numbers[numbers.length - 1 - i];
           numbers[numbers.length - 1 - i] = temp;
        } 
        System.out.println("\nArray after reverse:");
        for (int i = 0; i < numbers.length; i++) {
           System.out.print(numbers[i] + " ");
        } 
     }
  }
  

  上面的代码示例将产生以下结果。

  
  Array before reverse:
  1 2 3 4 5 6 7 8 9 10 
  Array after reverse:
  10 9 8 7 6 5 4 3 2 1