java - 一次从数组中拉出 10 个项目的最佳方法

Question

我有一个可以包含无限数量对象的 ArrayList。我需要一次拉取 10 个项目并对它们进行操作。

我能想到的就是这个。

int batchAmount = 10;
for (int i = 0; i < fullList.size(); i += batchAmount) {
    List<List<object>> batchList = new ArrayList();
    batchList.add(fullList.subList(i, Math.min(i + batchAmount, fullList.size()));
    // Here I can do another for loop in batchList and do operations on each item
}

有什么想法吗？谢谢!

Answer 1

你可以这样做:

int batchSize = 10;
ArrayList<Integer> batch = new ArrayList<Integer>();
for (int i = 0; i < fullList.size();i++) {
    batch.add(fullList.get(i));
    if (batch.size() % batchSize == 0 || i == (fullList.size()-1)) {
        //ToDo Process the batch;
        batch = new ArrayList<Integer>();
    }
}

当前实现的问题是您在每次迭代时创建一个 batchList，您需要在循环外声明此列表 (batchList)。像这样的东西:

int batchAmount = 10;
List<List<object>> batchList = new ArrayList();
for (int i = 0; i < fullList.size(); i += batchAmount) {
    ArrayList batch = new ArrayList(fullList.subList(i, Math.min(i + batchAmount, fullList.size()));
    batchList.add(batch);
 }
 // at this point, batchList will contain a list of batches