java如何获取只有迭代器的列表的“切片”？

Question

我有一个CSV文件，里面有从Fitbit下载的数据。CSV文件中的数据遵循基本格式：

<Type of Data>
<Columns-comma-separated>
<Data-related-to-columns>

以下是文件布局的一个小示例：

Activities
Date,Calories Burned,Steps,Distance,Floors,Minutes Sedentary,Minutes Lightly Active,Minutes Fairly Active,Minutes Very Active,Activity Calories
"2016-07-17","3,442","9,456","4.41","12","612","226","18","44","1,581"
"2016-07-18","2,199","7,136","3.33","10","370","93","12","46","1,092"
...other logs
Sleep
Date,Minutes Asleep,Minutes Awake,Number of Awakenings,Time in Bed
"2016-07-17","418","28","17","452"
"2016-07-18","389","26","10","419"

现在，我使用apachecommon库中的CSVParser来浏览这些数据。我的目标是将其转换为Java对象，将相关数据转换为Json（我需要将Json上传到其他网站）CSVParser有一个迭代器，我可以使用它来迭代文件中的CSVRecords。所以，基本上，我有一个所有数据的“列表”
因为该文件包含不同类型的数据（睡眠日志、活动日志等），所以我需要获得该文件的一个子列表，并将其传递到一个类中进行分析

我需要遍历列表并查找标识文件新部分的关键字（例如活动、食物、睡眠等）。一旦我确定了文件的下一部分是什么，我需要选择以下所有行，直到下一个类别

现在，对于这个问题中的问题：我不知道如何使用迭代器来获得List.sublist()的等价物。以下是我一直在尝试的：

while (iterator.hasNext())
{
    CSVRecord current = iterator.next();
    if (current.get(0).equals("Activities"))
    {
        iterator.next(); //Columns
        while (iterator.hasNext() && iterator.next().get(0).isData()) //isData isn't real, but I can't figure out what I need to do.
        {
            //How do I sublist it here?
        }
    }
}

因此，我需要确定下一个CSVRecord是否以quote/has数据开始，并循环直到找到下一个类别，最后将文件的一个子部分（使用迭代器）传递给另一个函数，以使用正确的日志执行某些操作

编辑

我考虑先用while循环将它转换成一个List，然后再进行子列表，但这似乎是浪费。如果我错了，请纠正我

此外，我不能假设每个部分后面都有相同数量的行。他们可能有相似的食物记录，但也有食物记录，它们遵循完全不同的模式。这里有两个不同的日子Foods遵循正常模式，但食物日志却没有

Foods
Date,Calories In
"2016-07-17","0"
"2016-07-18","1,101"

Food Log 20160717
Daily Totals
"","Calories","0"
"","Fat","0 g"
"","Fiber","0 g"
"","Carbs","0 g"
"","Sodium","0 mg"
"","Protein","0 g"
"","Water","0 fl oz"

Food Log 20160718
Meal,Food,Calories
"Lunch"
"","Raspberry Yogurt","190"
"","Almond Sweet & Salty Granola Bar","140"
"","Goldfish Baked Snack Crackers, Cheddar","140"
"","Bagels, Whole Wheat","190"
"","Braided Twists Honey Wheat Pretzels","343"
"","Apples, raw, gala, with skin - 1 medium","98"
"Daily Totals"
"","Calories","1,101"
"","Fat","21 g"
"","Fiber","13 g"
"","Carbs","202 g"
"","Sodium","1,538 mg"
"","Protein","28 g"
"","Water","24 fl oz"

Answer 1

做你想做的事情最简单的方法就是简单地记住以前的分类数据，当你点击一个新的分类时，处理以前的分类数据并为下一个分类重置。这应该起作用：

String categoryName = null;
List<List<String>> categoryData = new ArrayList<>();
while (iterator.hasNext()) {
    CSVRecord current = iterator.next();
    if (current.size() == 1) { //start of next category
        processCategory(categoryName, categoryData);
        categoryName = current.get(0);
        categoryData.clear();
        iterator.next(); //skip header
    } else { //category data
        List<String> rowData = new ArrayList<>(current.size());
        CollectionUtils.addAll(rowData, current.iterator()); //uses Apache Commons Collections, but you can use whatever
        categoryData.add(rowData);
    }
}
processCategory(categoryName, categoryData); //last category of file

然后：

void processCategory(String categoryName, List<List<String>> categoryData) {
    if (categoryName != null) { //first category of the file, skip
        //do stuff
    }
}

上面假设List<List<String>>是您想要处理的数据结构，但是您可以根据需要进行调整。我甚至建议将List<Iterable<String>>传递给process方法（CSVRecord实现Iterable<String>），并在那里处理行数据

这肯定可以进一步清理，但它应该让你开始