Question

我希望将第5行中打印的值插入整数数组中。该文件包含整数值和字符串值 ****我还在学习过程**** 对不起，我稍微改了一下这个问题。谢谢

     File f = new File("SampleInput.txt");
          try{
               ArrayList<String> lines = get_arraylist_from_file(f);       
               for(int x =23; x < lines.size(); x++){
                   System.out.println(lines.get(x));
                   **enter code here**
               }
            }
    catch(Exception e){
        System.out.println("File not found!!!!");
    }
}
public static ArrayList<String> get_arraylist_from_file(File f) 
    throws FileNotFoundException {
    Scanner s;
    ArrayList<String> list = new ArrayList<String>();
    s = new Scanner(f);
    while (s.hasNext()) {
        list.add(s.next());
    }
    s.close();
    return list;
}

Answer 1

      List<Integer> numList = new ArrayList<>();
      File f = new File("SampleInput.txt");
      try{
           ArrayList<String> lines = get_arraylist_from_file(f);       
           for(int x =23; x < lines.size(); x++){
               System.out.println(lines.get(x));
               **enter code here**
               numList.add(Integer.parseInt(lines.get(x))); 
           }
        }

Answer 2

更容易使用整数的ArrayList，如下所示

List<Integer> list = new ArrayList<Integer>();
File f = new File("SampleInput.txt");
          try{
               ArrayList<String> lines = get_arraylist_from_file(f);       
               for(int x =23; x < lines.size(); x++){
                   System.out.println(lines.get(x));
                   list.add(Integer.parseInt(lines.get(x)));
               }
            }
    catch(Exception e){
        System.out.println("File not found!!!!");
    }
}

Answer 3

我猜你想要这样的东西，

try{
  ArrayList<String> lines = get_arraylist_from_file(f);
  ArrayList<int> intLines = new ArrayList();
  for (int x = 23; x < lines.size(); x++) {
    System.out.println(lines.get(x));
    intLines.add(Integer.parseInt(lines.get(x)));
  }
}

Answer 4

你必须在适当大小的循环之外创建一个int数组，然后只需解析字符串并将它们添加到循环中的数组中：

           ArrayList<String> lines = get_arraylist_from_file(f); 
           int[] intArray = new int[lines.size-23];
           for(int x =23; x < lines.size(); x++){
               System.out.println(lines.get(x));
               //**enter code here**
               String line = lines.get(x);
               intArray[x-23] = Integer.parseInt(line);
           }

从List类型字符串中将值插入整数数组

4 个答案: