如何压缩两个Java列表

Question

List<String> subjectArr = Arrays.asList<String>("aa", "bb", "cc");
List<Long> numArr = Arrays.asList<Long>(2L, 6L, 4L);

List<?> subjectNumArr = zip(subjectArr, numArr);
// subjectNumArr == [{'aa',2},{'bb',6},{'cc',4}]

Answer 1

使用map.entry 的ArrayList，检查两个arraylists是否大小相等（这似乎是您的要求），如下所示：

List<Map.Entry<String,Long>> subjectNumArr = new ArrayList<>(numArr.size());
if (subjectArr.size() == numArr.size()) {
    for (int i = 0; i < subjectArr.size(); ++i) {
        subjectNumArr.add(new AbstractMap.SimpleEntry<String, Long>(subjectArr.get(i), numArr.get(i));
    }   
}

你需要的代码就这些！

然后，要对结果进行迭代，请使用如下代码：

for (Map.Entry<String, Long> entry : subjectNumArr) {
    String key = entry.getKey(); 
    Long value = entry.getValue();
}

Map.Entry<String, Long> entry = subjectNumArr.get(i);