java - 读取 CSV 文件和 IF 语句值 0？

Question

此代码应该读取 csv 文件，使用数组将所有 Axillary (Array[2]) 添加在一起并求平均值。

唯一的变化是使用 IF 语句，因为我想根据 (Array[3]) 的值将数据拆分为两个不同的变量，这将是 1 或 2。并分别找到它们的平均值。

当我运行此代码时，两者的输出值为 0。

package javainputoutput;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.File;
import java.util.Scanner;

public class JavaInputOutput 
{
public static void main(String[] args) 
{
    int totalOverAxillary = 0;
    int countOverAxillary = 0;
    int totalLessAxillary = 0;
    int countLessAxillary = 0;

    String fileName = "haberman.txt";
    try
    {
        Scanner InputStream = new Scanner(new File(fileName));

        while (InputStream.hasNextLine())
        {
            String line = InputStream.nextLine();
            String[] ary = line.split(",");

            int noPosAxillary = Integer.parseInt(ary[2]);
            int survivalStatus = Integer.parseInt(ary[3]);

            if(survivalStatus == 1)
            {
                totalOverAxillary =+ noPosAxillary;
                countOverAxillary++; 
            }
            else if(survivalStatus == 2)
            {
                totalLessAxillary =+ noPosAxillary;
                countLessAxillary++;
            }
        }

        InputStream.close();

        int aveOverAxillary = totalOverAxillary / countOverAxillary;
        int aveLessAxillary = totalLessAxillary / countLessAxillary;

        System.out.print("The average number of positive axillary nodes "
                        + "for patients that survived 5 years or longer is "
                        +  aveOverAxillary);
        System.out.println();
        System.out.print("The average number of positive axillary nodes "
                        + "for patients that died within 5 years is "
                        + aveLessAxillary);
    }
    catch(FileNotFoundException e)
    {
        System.out.println("Cannot find file " + fileName);
    }
    catch(IOException e)
    {
        System.out.println("Problem with input from file " + fileName);
    }
}

}

Answer 1

看来您搞乱了 += 运算符。而不是这个:

totalOverAxillary =+ noPosAxillary;

应该是这样的:

totalOverAxillary += noPosAxillary;

您在两个地方出现了上述错误，请确保修复这两个地方。

这样做的效果是总值将等于最后一个值，而不是总和。当你将这些值除以计数时，计数可能小于值，整数除法结果为零。