Java 读取文件/扫描仪

Question

我是java初学者，我正在努力让这段代码正常工作。我正在尝试读取 CSV 文件，然后使用该数据计算平均值，然后返回平均值的最高最低值和平均值的摘要。

输入如下所示:

Alicia Marks,89,90,100,95,75,85,94,100,90,92

Bobby Ricks,98,79,87,79,9,98,7,19,98,78

输出应如下所示(数字不正确，仅作为示例):

Alicia Marks 85.5 B

Bobby Ricks 90.0 A-

...

High 98.2

Low 56.5

Average 78.3333

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;

public class Test
{

    public static void main(String[] args)
    {
        Test x = new Test();
        x.high();
    }

    public void high()
    {
        File file2 = new File("scores.csv");
        try
        {
            Scanner scanner = new Scanner(file2);
            while (scanner.hasNextLine())
            {
                String line2 = scanner.nextLine();
                String[] value2 = line2.split(",");

                // Converts String Array into Double Array
                double[] score = new double[value2.length];
                for (int i = 1; i < value2.length; i++)
                {
                    score[i] = Double.parseDouble(value2[i]);
                }

                // Finds the sum and then the average, adds it to a array List
                ArrayList<Double> av;
                av = new ArrayList<Double>();
                double sumNum = 0.0;
                for (double i : score)
                {
                    sumNum += i;
                }
                double aver = sumNum / 10;
                av.add(aver);

                double max = 0, min = 100;
                for (int a = 0; a < av.size(); a++)
                {
                    double s = av.get(a);
                    max = Math.max(max, s);
                    min = Math.min(min, s);
                    aver += s;
                }

                System.out.println("High " + max + "");
                System.out.println("Low " + min + "");
                System.out.println("Average " + aver / av.size() + "");

            }
            scanner.close();
        }
        catch (FileNotFoundException e)
        {
            e.printStackTrace();
        }
    }
}

我认为我遇到的问题是 while 循环，但我不太确定。任何解决此问题的帮助将不胜感激。

Answer 1

读取成绩的函数中存在一个错误。您应该按以下方式修复它:

// Converts String Array into Double Array
double[] score = new double[value2.length - 1];
for (int i = 1; i < value2.length; i++) {
    score[i - 1] = Double.parseDouble(value2[i]);
}

据我所知，您需要所有成绩的最大值、最小值和平均值。那么你的代码应该是这样的:

package it.unitn.uvq.antonio.processor;

import java.io.File;
import java.io.FileNotFoundException;    
import java.util.ArrayList;
import java.util.Scanner;

public class Test {

    public static void main(String[] args) {
        Test x = new Test();
        x.high();
    }

    public void high() {
        File file2 = new File("/home/antonio/Scrivania/scores.csv");
        try {
            Scanner scanner = new Scanner(file2);
            ArrayList<Double> avgs = new ArrayList<>();
            double max = 0, min = 100;
            while (scanner.hasNextLine()) {
                String line2 = scanner.nextLine();
                String[] value2 = line2.split(",");

                // Converts String Array into Double Array
                double[] score = new double[value2.length - 1];
                for (int i = 1; i < value2.length; i++) {
                    score[i - 1] = Double.parseDouble(value2[i]);
                }

                // Finds the sum and then the average, adds it to a array List
                double sumNum = 0.0;
                for (double i : score) {
                    sumNum += i;
                    min = Math.min(min, i);
                    max = Math.max(max, i);
                }
                double avg = sumNum / 10;
                avgs.add(avg);

                System.out.println(avg);
            }
            scanner.close();
            double avgsSum = .0;
            for (double avg : avgs) {
                avgsSum += avg;
            }
            System.out.println("High " + max + "");
            System.out.println("Low " + min + "");
            System.out.println("Average " + avgsSum / avgs.size() + "");
        }
        catch (FileNotFoundException e) { 
            e.printStackTrace();
        }
    }
}