根据喜好对一群人进行排序。

Question

我正在设计一个群组生成器，它可以接收诸如 "混合性别"、"混合国籍 "等偏好... 我正在把一个学生的名字列表，然后是国籍和基因组，放在一个数组列表中。有什么最简单的方法可以根据用户的输入生成组，使每个组由来自不同国籍的人组成，或平衡性别。

 public ArrayList<String> readEachWord(String className)
    {
        ArrayList<String> readword = new ArrayList<String>();
        Scanner sc2 = null;
        try {
        sc2 = new Scanner(new File(className + ".txt"));
    } catch (FileNotFoundException e) {

        System.out.println("error, didnt find file");
        e.printStackTrace();  
    }
    while (sc2.hasNextLine()) {
            Scanner s2 = new Scanner(sc2.nextLine());
        while (s2.hasNext()) {
            String s = s2.next();
            readword.add(s);
        }
    }
    return readword;


    }

我正在用这个方法读取一个文本文件，每一行都有每个学生的姓名国籍和性别。我把它们放到一个ArrayList中，现在正试图弄清楚如何根据用户所需的组数来平均分配它们。

我使用一个txt文件来存储所有的信息，因为这个分组生成器是为我的学校定制的。

Answer 1

这里有一个东西可以让你开始。这个简短的algo会根据指定的歧视因素（国籍，性别等）对人进行排序，然后将他们平均分配到指定数量的组中。

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.Function;
import java.util.stream.Collectors;

public class Main {

    private static class Person {
        private String nationality;
        private String gender;

        public Person(String nationality, String gender) {
            this.nationality = nationality;
            this.gender = gender;
        }


        public String getNationality() {
            return nationality;
        }

        public String getGender() {
            return gender;
        }

        @Override
        public String toString() {
            return "Person{" +
                    "nationality='" + nationality + "'" +
                    ", gender='" + gender + "'" +
                    "}";
        }
    }

    public static void main(String[] args) {
        List<Person> people = Arrays.asList(
            new Person("DE", "male"),
            new Person("DE", "female"),
            new Person("DE", "n/a"),
            new Person("UK", "female"),
            new Person("UK", "female"),
            new Person("UK", "female"),
            new Person("JP", "trans"),
            new Person("JP", "male")
        );


        int number_of_groups = 3;

        Function<Person, String> discriminator = Person::getGender;

        AtomicInteger index = new AtomicInteger();
        List<List<Person>> groups = new ArrayList<>(people.stream()
                .sorted(Comparator.comparing(discriminator))
                .collect(Collectors.groupingBy(e -> index.getAndIncrement() % number_of_groups))
                .values());

        groups.forEach(System.out::println);
    }
}

输出。

[Person{nationality='DE', gender='female'}, Person{nationality='UK', gender='female'}, Person{nationality='JP', gender='trans'}]
[Person{nationality='UK', gender='female'}, Person{nationality='DE', gender='male'}]
[Person{nationality='UK', gender='female'}, Person{nationality='DE', gender='n/a'}]