Question

我的任务是在ArrayList的新手Java教程中执行以下操作

// 1) Declare am ArrayList of strings
    // 2) Call the add method and add 10 random strings
    // 3) Iterate through all the elements in the ArrayList
    // 4) Remove the first and last element of the ArrayList
    // 5) Iterate through all the elements in the ArrayList, again.

以下是我的代码

import java.util.ArrayList;
import java.util.Random;

public class Ex1_BasicArrayList {

    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<String>();
        for (int i = 0; i <= 10; i++){
            Random rand = new Random();
            String randy = String.valueOf(rand);
            list.add(randy );
        }
        for (int i = 0; i < list.size(); i++){
            System.out.print(list.get(i));
        }   
        list.remove(0);
        list.remove(list.size());

        for (int i = 0; i < list.size(); i++){
            System.out.print(list.get(i));
        }
    }
}

代码运行，但运行时收到以下错误消息。关于我做错什么的任何想法？

java.util.Random@7852e922java.util.Random@4e25154fjava.util.Random@70dea4ejava.util.Random@5c647e05java.util.Random@33909752java.util.Random@55f96302java.util.Random@3d4eac69java.util.Random@42a57993java.util.Random@75b84c92java.util.Random@6bc7c054Exception in thread "main" java.lang.IndexOutOfBoundsException: Index: 10, Size: 10
    at java.util.ArrayList.rangeCheck(Unknown Source)
    at java.util.ArrayList.remove(Unknown Source)
    at apollo.exercises.ch08_collections.Ex1_BasicArrayList.main(Ex1_BasicArrayList.java:23)

Answer 1

List个索引从0转到list.size() - 1。超过上限导致IndexOutOfBoundsException

list.remove(list.size() - 1);

Answer 2

你的清单有11个元素，它们的索引是0-10。当你调用list.remove(list.size());时，你告诉它删除索引11处的元素（因为列表的大小是11），但该索引超出范围。

任何列表的最后一个元素的索引始终为list.size() - 1。

删除列表的最后一个元素

2 个答案: