Question

我已经在单元格++中创建了一个双打的ArrayList，它应该存储扫描程序检测到的所有双精度值。但是，当我运行代码时，程序会一直要求下一个输入，我不知道为什么。

例如，如果我的输入是2,3,9，我希望程序将值2存储到arraylist的第一个单元格，将值3存储到第二个单元格，将值9存储到第三个单元格。问题是，如果我在我的交互窗格中填写2,3,9，它会一直要求下一个输入。

  ArrayList<Double> doubleList;
  doubleList = new ArrayList<Double>();

  while (scanner.hasNextDouble()) {
      doubleList.add(scanner.nextDouble());
  }

Answer 1

Is this what you want to do?  Hope it helps.

I have a test.txt file 
and it has 
2
3
4
9

running will give you output:

[2.0]
[2.0, 3.0]
[2.0, 3.0, 4.0]
[2.0, 3.0, 4.0, 9.0]



  public class test2 {

  public static void main(String[] args)  throws FileNotFoundException
  {
    ArrayList<Double> doubleList;
      doubleList = new ArrayList<Double>();
      File myFile = new File("C:\\test.txt");
      Scanner scanner = new Scanner(myFile);

      while (scanner.hasNext() ) {
          if (scanner.hasNextDouble())
              doubleList.add(scanner.nextDouble());
          System.out.println(doubleList.toString());

      }
   }


  }

遇到ArrayList和scanner.hasNext的问题

1 个答案: