如何在两个相同大小的集合中进行操作

Question

Assuming there are two same size Integer ArrayLists, is there a more efficient way to get a list back which is composed of the difference between the two lists?
My solution is very simple but seems not good, just post it anyway:

// Assuming two same size list
List<Integer> listA = Arrays.asList(91,81,76,66,52);
List<Integer> listB = Arrays.asList(11,24,36,40,53);
List<Integer> diffList = new ArrayList<Integer>();
// I expect to get [80, 57, 40, 26, -1] back
for(int i = 0 ; i < listA.size(); i++){
    diffList.add(listA.get(i)-listB.get(i));
}

But I thought it was not a good solution. Anyone has better idea to solve this question by Java 8 Stream or some data structure else?

Answer 1

Since the question is tagged with java-stream , hence a suggestion that you can use:

List<Integer> diffList = IntStream.range(0, listA.size())
        .mapToObj(i -> listA.get(i) - listB.get(i))
        .collect(Collectors.toList());

Answer 2

Thanks for @nullpointer 's help, I got idea for if the two list size is not equivalent.

    boolean isALonger;
    if (listA.size() > listB.size()) {
        isALonger = true;
    } else {
        isALonger = false;
    }
    List<Integer> integers = IntStream.range(0, isALonger?listA.size():listB.size()).mapToObj(i -> {
        if (isALonger) {
            if (i < listB.size()) {
                return listA.get(i) - listB.get(i);
            } else {
                return listA.get(i);
            }
        } else {
            if (i < listA.size()) {
                return listA.get(i) - listB.get(i);
            } else {
                return - listB.get(i);
            }
        }
    }).collect(Collectors.toList());  

---

Thanks for Holger 's advices. I fixed code below:

    int minSize = Math.min(listA.size(), listB.size());
    int maxSize = Math.max(listA.size(), listB.size());
    Stream<Integer> diffPart = IntStream.range(0, minSize).mapToObj(i -> listA.get(i) - listB.get(i));
    Stream<Integer> restPart = IntStream.range(minSize, maxSize).mapToObj(i -> listA.size() > listB.size() ? listA.get(i) :
            -listB.get(i));
    List<Integer> collect = Stream.concat(diffPart, restPart).collect(Collectors.toList());