爪哇 - 多维数组或多维的ArrayLists的ArrayList的数组列表？ [英] Java - arraylist of multidimensional arrays or arraylist of multidimensional arraylists?

问题描述

我学习Java和我试图环绕这些数据结构我的头。我在Python / PHP的未来，所以我用动态大小动态数组，并能够多种类型的数据存储在一个数组中。

I'm learning Java and am trying to wrap my head around these data structures. I'm coming from Python/PHP so I'm used to dynamically sizing arrays on the fly and being able to store multiple data types in one array.

如何将我最好的存储这些数据？说我不知道​​我有多少行会有，但我知道每一行将于2数据列。一列是一个字符串，而另一列属双层。

How would I best store this data? Say I don't know how many rows I'll have, but I do know that each row will hold 2 columns of data. One column being a string, and the other column being a double.

例伪上下的code，如果我有3行：

Example in pseudo-ish code if I had 3 rows:

array(array("description1", 10.00),
      array("description2", 12.00),
      array("description3", 14.00));

然后，我想遍历数组处理datawith是这样的：

Then, I want to loop through the array to process the datawith something like:

foreach(rows as row){
    myStringVal = row[0]; //on first iteration would be "description1"
    myIntVal = row[1];    //on first iteration would be 10.00
    ... do something with the values ...
}

我想我需要创建一个保存了数组一个ArrayList，但我不能存储在一个Java数组字符串和双打，所以我该怎么办？难道我使用地图来代替，并把它当作好像它是一个数组？例如，做我创建了一个地图，第一个元素是各行的数字ID，第二个元素是字符串值，第三个元素是双重价值，然后我用一个循环，增加一个计数器，并抓住每行从用数字标识的地图>

I'm thinking I need to create an arraylist that holds an array, but I can't store both strings and doubles in a java array, so what do i do? Do I use a map instead, and treat it as if it were an array? For example, do I create a map where the first element is a numeric ID for each row, the second element is the string value, the 3rd element is the double value, and then I use a loop to increase a counter and grab each row from the map that using the numeric ID>

真的困惑，这将如何工作。有什么建议么？谢谢！

Really confused as to how this will work. Any suggestions? Thanks!

推荐答案

您不是存储别样的价值观，你存储的语义数据连接codeS一个元组，但使用非的只是粘附在阵列的java概念。不这样做，而是使用编码链接数据的C / C ++ / Java的概念，作为一个结构/对象：

You're not storing "different kind of values", you're storing semantic data that encodes "a tuple" but using the non-java concept of just sticking that in an array. Don't do that, instead use the C/C++/Java concept of encoding linked data as a struct/object:

// our "struct"esque class for the linked data we're handling
class MyObject {
  String description;
  float value;
  Public MyObject(String description, float value) {
    this.description = description;
    this.value = value;
  }
}

// build our list of objects
ArrayList<MyObject> mylist = new ArrayList<MyObject>();
mylist.add(new MyObject("description1", 10));
mylist.add(new MyObject("description2", 12));
mylist.add(new MyObject("description3", 14));
...

// and then we iterate
String d; float v;
for(MyObject m: mylist) {
  d = m.description;
  v = m.value;
  ...
}

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