英文:
How I can sort a list of list in java?
问题
我想对一个列表的列表进行排序，示例：
List<List<String>> listOflists = new ArrayList();List<String> b = {"x", "x"};List<String> a = {"x"};List<String> c = {"x", "x", "x"};listOflists.add(a);listOflists.add(b);listOflists.add(c);//按数组大小排序List<String> sortedList = listOflists.stream().sorted().collect(Collectors.toList());
我预期在forEach过程中处理listOflists：
循环 1 x
循环 2 x,x
循环 3 x,x,x
英文:
I want to sort a list of lists, example:
List<List<String>> listOflists = new ArrayList();List<String> b = {"x", "x"};List<String> a = {"x"};List<String> c = {"x", "x", "x"};listOflists.add(a);listOflists.add(b);listOflists.add(c);//Oder by size of the arrayList<String> sortedList = listOflists.stream().sorted().collect(Collectors.toList());
I expected that listOflists in a forEach process:
Lopp 1 x
Lopp 2 x,x
Lopp 3 x,x,x
答案1
得分: 1
[Arrays.compare](https://docs.oracle.com/en/java/javase/14/docs/api/java.base/java/util/Arrays.html#compare(T%5B%5D,T%5B%5D)) 函数用于比较两个对象数组，比较的是具有可比性的元素的字典顺序。试一试：List<List<String>> listOflists = Arrays.asList(Arrays.asList("x", "x"),Arrays.asList("x"),Arrays.asList("x", "x", "x"));List<List<String>> sortedList = listOflists.stream().map(list -> list.toArray(String[]::new)).sorted((x, y) -> Arrays.compare(x, y)).map(array -> Arrays.asList(array)).collect(Collectors.toList());System.out.println(sortedList);输出结果：[[x], [x, x], [x, x, x]]如果你想根据列表大小进行排序：List<List<String>> sortedList = listOflists.stream().sorted(Comparator.comparing(list -> list.size())).collect(Collectors.toList());
英文:
Arrays.compare compares two Object arrays, within comparable elements, lexicographically.
Try this.
List<List<String>> listOflists = Arrays.asList(Arrays.asList("x", "x"),Arrays.asList("x"),Arrays.asList("x", "x", "x"));List<List<String>> sortedList = listOflists.stream().map(list -> list.toArray(String[]::new)).sorted((x, y) -> Arrays.compare(x, y)).map(array -> Arrays.asList(array)).collect(Collectors.toList());System.out.println(sortedList);
output:
[[x], [x, x], [x, x, x]]
If you want to sort by list size.
List<List<String>> sortedList = listOflists.stream().sorted(Comparator.comparing(list -> list.size())).collect(Collectors.toList());
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论