从文件的ArrayList（具体格式） [英] ArrayList from file (specific format)

问题描述

我有一个看起来像这样的文件：

  1日2次n次
    E1 V1 1
    E1 V3 2
    E1 V4 4
    E1 V5 7
    E2 V1 1
    。 。 。
    。 。 。
    。 。 。
 

我想的第一列是数组列表（E1，E2或或E3），我想第二列有它的价值（一个int），第n个指标里面的名字。

我会如何做呢？

您想对我是什么意思进一步澄清标识，请不要害怕离开时。

P.S。这是一个更大的项目的一部分，但我有种停留在数据的格式。

我假设我将不得不寻找与名字（第一列）一个ArrayList，如果我找到它，然后在第n个值（第3列）增加值（第2列），如果我并不觉得，我做一个ArrayList中，然后执行上述

更新

所以我设法让程序几乎工作 - 我不能使用的ArrayList的原始结构，因为所有的变量都在编译期间被宣布 - 后不能宣布。
我决定用一个HashMap，键具有第一个值，而第二个值的第n个位置一个ArrayList

 `的HashMap＆LT;弦乐，ArrayList的＆LT;整数GT;＆GT; userRatings =新的HashMap＆LT;弦乐，ArrayList的＆LT;整数GT;＆GT;（）;
 如果（！userRatings.containsKey（用户））//用户没有评级。
                {
                    ArrayList的＆LT;整数GT;收视率=新的ArrayList＆LT;整数GT;（）;
                    //收视率= userRatings.get（用户）;
                   对于（INT J = 0; J＆LT; 50; J ++）
                    {
                        ratings.add（J）;
                    }
                    userRatings.get（用户）。新增（位置值）;
}}
                否则//用户有评级
                {
                    userRatings.get（用户）。新增（位置值）; **
                }
                的System.out.println（用户++ userRatings.get（用户））;
            }
            bufferReader.close（）;
        }赶上（FileNotFoundException异常E）
        {
            的System.out.println（文件不存在或无法找到。）;
        }
        赶上（IOException异常E）
        {
            的System.out.println（无法从文件读取）;
        }
        赶上（NullPointerException异常E）
        {
        }`
 

这个问题我现在是加入到ArrayList。我会怎么做，在粗体领域？ - 我将如何填充和操纵的ArrayList

？

解决方案

  

说实话，我觉得最初的问题是阅读文件
  该格式。

如果你使用正确的库这很容易。看看这个： http://opencsv.sourceforge.net/ 的，其目的是要分析CSV文件。从该网站：

  

我可以用我自己的分隔符和引号字符？

  
  

是的。有
  这迎合提供自己的分隔符，报价构造
  字符。假设你正在使用您的分离选项卡，你可以做
  是这样的：

  CSVReader读卡器=新CSVReader（新的FileReader（yourfile.csv），\\ t'）;
 

我觉得这是你想要做什么。你问这个库来解析与制表符分隔值而不是逗号分隔的输入文件。从上面的例子中，这似乎是你的输入格式是什么。

I have a file that looks like this:

    1st ­ ­ ­   ­­­ 2nd ­ ­ ­   ­­­ nth
    e1­ ­ ­ ­   ­­­ ­­v1 ­ ­ ­   ­­­ 1
    e1 ­ ­ ­   ­­­ v3 ­ ­ ­   ­­­ 2
    e1 ­ ­ ­   ­­­ v4 ­ ­ ­   ­­­ 4
    e1 ­ ­ ­   ­­­ v5 ­ ­ ­   ­­­ 7
    e2 ­ ­ ­   ­­­ v1 ­ ­ ­   ­­­ 1
    . ­ ­ ­   ­ ­ ­. ­ ­ ­  ­ ­ ­­­ .
    . ­ ­ ­   ­ ­ ­. ­ ­ ­   ­­­  .
    . ­ ­ ­   ­ ­ ­.      ­  .

I want the first column to be the name of the arraylist (e1, or e2, or e3), I want the second column to have it's value (an int), inside the nth index.

How would I go about doing that?

Id you'd like further clarification on what I mean, please don't be afraid to leave a pm.

p.s. This is part of a bigger project, but I'm kind of stuck at the format of the data.

I'm assuming i'll have to look for an arraylist with the the name (first column) and if i find it, then add the value (2nd column) at the nth value (3rd column), and if I don't find it, I make an arrayList, and THEN do the aforementioned.

Update

So I managed to get the program almost working -- I couldn't use the original structure of ArrayLists because all variables have to be declared during compilation -- can't be declared after. I decided to use a hashmap, with the key has the 1st value, and an arraylist of the 2nd values in the nth position:

`HashMap<String, ArrayList<Integer>> userRatings = new HashMap<String, ArrayList<Integer>>();
 if(!userRatings.containsKey(user)) //The user does not have ratings.
                {
                    ArrayList<Integer> ratings = new ArrayList<Integer>();
                    //                     ratings = userRatings.get(user);
                   for (int j = 0; j < 50; j++)
                    {
                        ratings.add(j);
                    }
                    userRatings.get(user).add(location,value);
}                }
                else //The user has ratings
                {
                    userRatings.get(user).add(location,value);**
                }
                System.out.println(user + " " + userRatings.get(user));
            }
            bufferReader.close();
        }    catch (FileNotFoundException e)
        {
            System.out.println("File does not exist or could not be found.");
        }
        catch (IOException e)
        {
            System.out.println("Can't read from file");
        }
        catch (NullPointerException e)
        {
        }`

The problem I now have is in adding to the arraylist. How would I do that in the bolded areas? -- How would I populate and manipulate the arraylist?

解决方案

To be honest, I think the initial problem is in reading the file in that format.

This is easy if you use the right library. Take a look at this one: http://opencsv.sourceforge.net/, which is meant to parse csv files. From that site:

Can I use my own separators and quote characters?

Yes. There are constructors that cater for supplying your own separator and quote characters. Say you're using a tab for your separator, you can do something like this:

CSVReader reader = new CSVReader(new FileReader("yourfile.csv"), '\t');

I think this is exactly what you're trying to do. You're asking this library to parse the input file with tab-delimited values instead of comma-delimited. From your example above, that seems to be what your input format is.

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