如何使用多维arraylist? [英] how to work with Multidimensional arraylist?

问题描述

嘿，抱歉，我是Java的菜鸟，但我想做点什么，我需要一个多维数组列表.必须将其实现为以下代码:

Hey guys sorry i'm a noob at java but im trying to make something and i need a multidimensional array list. It must be implemented into the following code:

public static void OpenFile() {
 ArrayList<ArrayList<String>> array = new ArrayList<ArrayList<String>>();
    int retrival = chooser.showOpenDialog(null);
    if (retrival == JFileChooser.APPROVE_OPTION) {
        try (BufferedReader br = new BufferedReader(new FileReader(
                chooser.getSelectedFile()))) {
            String sCurrentLine;
            while ((sCurrentLine = br.readLine()) != null) {
                if (sCurrentLine.equals("")) {
                    continue;
                } else if (sCurrentLine.startsWith("Question")) {
                    System.out.println(sCurrentLine.split(":")[1]);
                    //add to [0] in array ArrayList
                } else if (sCurrentLine.startsWith("Answer")) {
                    System.out.println(sCurrentLine.split(":")[1]);
                    //add to [1] in array ArrayList
                } else if (sCurrentLine.startsWith("Category")) {
                    System.out.println(sCurrentLine.split(":")[1]);
                    //add to [2] in array ArrayList
                } else if (sCurrentLine.startsWith("Essay")) {
                    System.out.println(sCurrentLine.split(":")[1]);
                    //add to [3] in array ArrayList
                }
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

我分割的所有字符串[1]索引都需要按以下顺序放入多维数组:问题，答案，类别和论文.
所以我目前正在使用普通的多维数组，但您不能轻松更改其值.我希望我的多维数组列表看起来像这样:

All the [1] index's of the strings i split need to go into a multidimesional array in this order: question, answer, category, essay.
So i am currently using a normal multidimensional array but you cant change the values of it easily. What i want my multidimensional arraylist to look like is this:

多维ArrayList

MultiDimensional ArrayList

• [0]:问题(可能超过100个.)
• [1]个答案(可能超过100个.)
• [2]类别(可能超过100个.)
• [3]文章(可能超过100篇)

推荐答案

似乎是带有列表列表"的作业.

Seems like an assignment with List of List.

这是伪代码.尝试实现休息.

Here is the psuedo code. Try to implement rest.

 ArrayList<ArrayList<String>> array = new ArrayList<ArrayList<String>>();

您要做的第一件事是获取4个新的ArrayLists

First thing you have to do is take 4 fresh ArrayLists

 ArrayList<String> qtns= new ArrayList<String>>();
 ArrayList<String> answrs= new ArrayList<String>>();
--
--

将它们全部添加到主列表

Add all of them to main list

array.add(qtns);
--
--

然后像这样填充它们

     else if (sCurrentLine.startsWith("Question")) {
                        System.out.println(sCurrentLine.split(":")[1]);
                        //add to [0] in array ArrayList
                        array.get(0).add(sCurrentLine.split(":")[1]);//get first list(which is qtns list) and add to it.
     } else if (sCurrentLine.startsWith("Answer")) {
                    System.out.println(sCurrentLine.split(":")[1]);
                    //add to [1] in array ArrayList
 array.get(1).add(sCurrentLine.split(":")[1]);//get second list(which is answers list) and add to it.
                }
    -- -
    ---

这样一来，您最终将获得一个包含数据的列表列表.

So that in the end you'll have a list of list which contains the data.

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