Java代码实现统计每个地区居住的人名

List<String> list = new ArrayList<>();
Map<String, List<String>> map = new HashMap<>();
for (String s : list) {
    String[] arr = s.split(',');
    String name = arr[0];
    String location = arr[1];
    if (map.containsKey(location)) {
        map.get(location).add(name);
    } else {
        List<String> nameList = new ArrayList<>();
        nameList.add(name);
        map.put(location, nameList);
    }
}