如何对 3 类列表中的列表进行排序 [关闭]

Question

我想根据许多列对列表进行排序，但我不知道如何进行。

输入：

List<String> a = ["TEAMA", "COUNTRYA", "AGEA", "PLAYERA"]
List<String> b = ["TEAMB", "COUNTRYF", "AGEA", "PLAYERB"]
List<String> c = ["TEAMC", "COUNTRYR", "AGEB", "PLAYERC"]
List<String> d = ["TEAMB", "COUNTRYF", "AGEC", "PLAYERD"]
List<String> e = ["TEAMA", "COUNTRYA", "AGEA", "PLAYERE"]
List<String> f = ["TEAMA", "COUNTRYF", "AGEE", "PLAYERF"]
List<List<String>> FinalList = []
FinalList.add(a)
FinalList.add(b)
FinalList.add(c)
FinalList.add(d)
FinalList.add(e)
FinalList.add(f)

输出：

["TEAMA", "COUNTRYA", "AGEA", "PLAYERA"]
["TEAMA", "COUNTRYA", "AGEA", "PLAYERE"]
["TEAMA", "COUNTRYF", "AGEE", "PLAYERF"]
["TEAMB", "COUNTRYF", "AGEA", PLAYERB"]
["TEAMB", "COUNTRYF", "AGEC", "PLAYERD"]
["TEAMC", "COUNTRYR", "AGEB", "PLAYERC"]

我该如何处理它？

Answer 1

我已经在您之前的一篇文章中提供了答案。我们没有一个字符串列表，而是将其表示为一个普通的旧 java 对象，称为 Entity（给它一个更好的名称）。然后我们从所有 Entity 对象创建一个 List，并根据团队进行排序。如果您想按国家或球员进行排序，您可以轻松做到。

1. 创建一个 POJO 来表示这些字符串值。

   private static final class Entity {

        private final String team;

        private final String country;

        private final String age;

        private final String player;

        private Entity(String team, String country, String age, String player) {
            this.team = team;
            this.country = country;
            this.age = age;
            this.player = player;
        }

        public String getTeam() {
            return team;
        }

        public String getCountry() {
            return country;
        }

        public String getAge() {
            return age;
        }

        public String getPlayer() {
            return player;
        }
    }

创建一些 Comparator 对象以重复使用，以便您可以按不同的属性进行排序。

    private static final Comparator<Entity> SORT_BY_TEAM = Comparator.comparing(Entity::getTeam);

    private static final Comparator<Entity> SORT_BY_COUNTRY = Comparator.comparing(Entity::getCountry);

    private static final Comparator<Entity> SORT_BY_AGE = Comparator.comparing(Entity::getAge);

    private static final Comparator<Entity> SORT_BY_PLAYER = Comparator.comparing(Entity::getPlayer);

    public static void main(String[] args) {
        List<Entity> entities = new ArrayList<>(Arrays.asList(
                new Entity("TEAMA", "COUNTRYA", "AGEA", "PLAYERA"),
                new Entity("TEAMA", "COUNTRYA", "AGEA", "PLAYERE"),
                new Entity("TEAMA", "COUNTRYF", "AGEE", "PLAYERF"),
                new Entity("TEAMB", "COUNTRYF", "AGEA", "PLAYERB"),
                new Entity("TEAMB", "COUNTRYF", "AGEC", "PLAYERD"),
                new Entity("TEAMC", "COUNTRYR", "AGEB", "PLAYERC")));

        List<Entity> sortedByTeam = entities.stream().sorted(SORT_BY_TEAM).collect(Collectors.toList());

        List<Entity> sortedByAge = entities.stream().sorted(SORT_BY_AGE).collect(Collectors.toList());

        List<Entity> sortedByCountry = entities.stream().sorted(SORT_BY_COUNTRY).collect(Collectors.toList());

        List<Entity> sortedByPlayer = entities.stream().sorted(SORT_BY_PLAYER).collect(Collectors.toList());
    }

Answer 2

您可以创建与列一样多的比较器，并一次使用一个或链接它们以按多个排序标准进行排序：

Comparator<List<String>> byIndex0 = Comparator.comparing(i -> i.get(0));
Comparator<List<String>> byIndex1 = Comparator.comparing(i -> i.get(1));
Comparator<List<String>> byIndex2 = Comparator.comparing(i -> i.get(2));
Comparator<List<String>> byIndex3 = Comparator.comparing(i -> i.get(3));

按期望的标准对最终列表进行排序，例如。按第一个索引（团队）

FinalList.sort( byIndex0 );

要按两个标准排序，您可以使用#thenComparing 将它们链接起来，例如。按团队然后按国家/地区

FinalList.sort( byIndex0.thenComparing(byIndex1));

或全部使用：

FinalList.sort( byIndex0.thenComparing(byIndex1).thenComparing(byIndex2).thenComparing(byIndex3));

Answer 3

public class SortListExample {
    public static void main(String[] args) {
        List<String> a = Arrays.asList("TEAMA", "COUNTRYA", "PLAYERA");
        List<String> b = Arrays.asList("TEAMB", "COUNTRYF", "PLAYERB");
        List<String> c = Arrays.asList("TEAMC", "COUNTRYR", "PLAYERC");
        List<String> d = Arrays.asList("TEAMB", "COUNTRYA", "PLAYERD");
        List<String> e = Arrays.asList("TEAMA", "COUNTRYA", "PLAYERE");
        List<String> f = Arrays.asList("TEAMA", "COUNTRYF", "PLAYERF");
        List<List<String>> FinalList = new ArrayList<>();
        FinalList.add(a);
        FinalList.add(b);
        FinalList.add(c);
        FinalList.add(d);
        FinalList.add(e);
        FinalList.add(f);
        List<List<String>> listToSort = new ArrayList<>(FinalList);
        listToSort.sort((l1, l2) -> {
            int i = 0;
            while (true) {
                if (l1.get(i) != null && l2.get(i) != null) {
                    int compareVal = l1.get(i).compareTo(l2.get(i));
                    if (compareVal != 0) {
                        return compareVal;
                    }
                    i++;
                }
            }
        });
        for (List<String> list: listToSort) {
        System.out.println(list);
    }
    }
}

Answer 4

您只需检索链接列表的值，然后存储和排序从同一列（或索引）检索的值。还要确保在代码中包含所有引号。