Question

所以我一直致力于从列表中读取数组并使用内容进行计算。

我有数组部分=

[Mildred, Bush, 45, 65, 45, 67, 65, Fred, Snooks, 23, 43, 54, 23, 76, Morvern, Callar, 65, 45, 34, 87, 76, Colin, Powell, 34, 54, 99, 67, 87, Tony, Blair, 67, 76, 54, 22, 12, Peter, Gregor, 99, 99, 99, 99, 99]

这里假设每7个值是文本文件的一行。所以我想要做的是取名字，将数字改成整数，然后进行计算然后输出它们。

我尝试使用的代码是：

for(int i=0; i < 42;i=i+7) {
    float avg;
    float total;
    for (int x=2; x < 7;x++) {
        String number = parts[x];
        int num = Integer.parseInt(number);
        total = total + num;
    }
    avg = total/6;
    System.out.print(parts[i+1] + "," + parts[i+2] + + "Final Score is avg");
}

但是我遇到了错误

The type of the expression must be an array type but it resolved to List<String>

所以我想知道如何解决这个问题

更新了试用：

String fileName =＆＃34; Details.txt＆＃34 ;;

    String wfilename = "output.txt";

    // This will reference one line at a time
    String line = null;

    String temp;

    try {
        // FileReader reads text files in the default encoding.
        FileReader fileReader = new FileReader(fileName);

        FileWriter fileWriter = new FileWriter(wfilename);


        BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);

        // Always wrap FileReader in BufferedReader.
        BufferedReader bufferedReader = new BufferedReader(fileReader);

        List<String> parts = new ArrayList<>();
        String [] temp2;

        while((line = bufferedReader.readLine()) != null) {
            System.out.println(line);
            temp = line;
            temp2 = line.split(" ");

            for(int i=0; i<7; i++){
                parts.add(temp2[i]);
           }
            //System.out.println(line);
            bufferedWriter.write(line + "\n");
        }   
        System.out.print(parts);

        //conver to an array of strings
        String[] partsArray = parts.toArray();

        //code to do take values from array, do calculations and format to output
        for(int i=0; i < 42;i=i+7) {
            float avg;
            float total = 0;
            for (int x=2; x < 7;x++) {
                String number = partsArray[x];
                int num = Integer.parseInt(number);
                total = total + num;
            }
            avg = total/6;
            System.out.print(partsArray[i+1] + "," + partsArray[i+2] + "Final Score is" + avg);
        }

        // Always close files.
        bufferedReader.close();   
        bufferedWriter.close();
    }
    catch(FileNotFoundException ex) {
        System.out.println("Unable to open file '" + fileName + "'");                
    }
    catch(IOException ex) {
        System.out.println("Error reading file '" + fileName + "'");                  

    }

Answer 1

你明确有一份清单。你可以把它变成一个数组，就像这个

String[] partsArray = parts.toArray(new String[parts.size()]);

或开始像列表一样访问它，如此

String number = parts.get(x);

Answer 2

.toArray（）应该可以解决问题。

例如：String[] partsArr = parts.toArray();

一些阅读材料：here

如何访问列表

2 个答案: