Java 批量循环数组列表
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Loop arraylist in batches
提问by Anand03
I want to iterate through an ArrayList in small batch sizes.
我想以小批量迭代 ArrayList。
For example, if the ArrayList size is 75 and the batch size is 10, I want it to process records 0-10, then 10-20, then 20-30, etc.
例如，如果 ArrayList 大小为 75，批处理大小为 10，我希望它处理记录 0-10，然后是 10-20，然后是 20-30，等等。
I tried this, but it did not work:
我试过这个，但没有用：
int batchSize = 10;
int start = 0;
int end = batchSize;
for(int counter = start ; counter < end ; counter ++)
{
if (start > list.size())
{
System.out.println("breaking");
break;
}
System.out.println("counter " + counter);
start = start + batchSize;
end = end + batchSize;
}
采纳答案by Karibasappa G C
You do it like remainder from batch size and list size to find count.
您可以像从批量大小和列表大小中取余一样来查找计数。
int batchSize = 10;
int start = 0;
int end = batchSize;
int count = list.size() / batchSize;
int remainder = list.size() % batchSize;
int counter = 0;
for(int i = 0 ; i < count ; i ++)
{
System.out.println("counter " + counter);
for(int counter = start ; counter < end ; counter ++)
{
//access array as a[counter]
}
start = start + batchSize;
end = end + batchSize;
}
if(remainder != 0)
{
end = end - batchSize + remainder;
for(int counter = start ; counter < end ; counter ++)
{
//access array as a[counter]
}
}
回答by Ash
int start = 0;
int end=updateBatchSize;
List finalList = null;
try {
while(end < sampleList.size()){
if(end==sampleList.size()){
break;
}
finalList = sampleList.subList(Math.max(0,start),Math.min(sampleList.size(),end));
start=Math.max(0,start+updateBatchSize);
end=Math.min(sampleList.size(),end+updateBatchSize);
}
回答by Tanmay Baid
What you need is: Lists.partition(java.util.List, int)from Google Guava
您需要的是：来自Google Guava 的Lists.partition(java.util.List, int)
Example:
例子：
final List<String> listToBatch = new ArrayList<>();
final List<List<String>> batch = Lists.partition(listToBatch, 10);
for (List<String> list : batch) {
// Add your code here
}
