Question

 import java.io.BufferedReader;
 import java.io.FileNotFoundException;
 import java.io.FileReader;
 import java.io.IOException;
 import java.io.InputStreamReader;

 public class CSVReader {
   public static void main(String[] args) {
    CSVReader obj = new CSVReader();
    obj.run();
 }

 public void run() {
  String CSVFile = "/Users/Wyatt/CSVFile2.csv";
  BufferedReader br = null;
  String Line = "";
  String analysisStr;
  String CSVDelimiter = ",";
  int analysis;
  double AVGDate = 0;

  BufferedReader console = new BufferedReader(new InputStreamReader(System.in));

  try {
      br = new BufferedReader(new FileReader(CSVFile));
      while ((Line = br.readLine()) != null) {
          String[] Weather = Line.split(CSVDelimiter);
          System.out.println("Weather [Date: " 
                      + Double.parseDouble(Weather[0]) + ", Interval: " 
                      + Double.parseDouble(Weather[1]) + ", Rainfall: " 
                      + Double.parseDouble(Weather[2]) + ", Sunlight: " 
                      + Double.parseDouble(Weather[3]) + ", Time: " 
          + Double.parseDouble(Weather[4]) + ", Total: " 
                     + Double.parseDouble(Weather[5]) + ", Overall: " 
                      + Double.parseDouble(Weather[6]) + "]");
          AVGDate = (Double.parseDouble(Weather[0]) / 804);
          System.out.println(AVGDate);
      }     

    System.out.println("What data is wanted?");
    analysisStr = console.readLine();
    analysis = Integer.parseInt(analysisStr);

    if(analysis == 0) {
        System.out.println("Date.");
        System.out.println("Minimum date is:");
        System.out.println("Maximum date is:");
        System.out.println("Average date is: " + AVGDate);
    }
    else if(analysis == 1) {
        System.out.println("Interval.");
        System.out.println("This data isn't useful.");
    }

} catch (FileNotFoundException e) {
    e.printStackTrace();
} catch (IOException e) {
    e.printStackTrace();    
} finally {
    if (br != null) {
        try {
            br.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

    System.out.println("Done.");

    }

   }

标题

上面的程序正确读取文件，读取并打印出所有记录，但是对于我的平均日期，它计算每个单独的记录日期而不是一起计算所有日期，我是新手用户，对Java来说真的很新，我我看不出自己做错了什么。另一个问题是我不知道如何计算每列的最小/最大数据。只是直截了当不确定如何做到这一点。

Answer 1

要计算平均值，您必须先计算总数并将其除以元素数。因此，每次读取数据时，都会初始化total并将其汇总到while循环中。

double total = 0.0

while(...) {
    ...
    total += Double.parseDouble(Weather[0]);
}
AVGDate = total / 804;

现在关于计算最小值或最大值......

double minDate = Double.MAX_VALUE;
double maxDate = Double.MIN_VALUE;
while(...) {
    // parse each data
    double temp = Weather[0];    
    if(temp < minDate) {
        minDate = temp;
    }

    else if(temp > maxDate) {
        maxDate = temp;
    }
}

还要记住，我们使用lower-case约定来进行非最终变量命名。

在CSV文件中的多个记录时打印出特定数据和计算

标题

1 个答案: