同时对两个 arrayList 进行排序 [英] Sort two arrayLists concurrently

问题描述

假设我有两个 ArrayList:

Say I have two ArrayLists:

name: [Four, Three, One, Two]
num:  [4, 3, 1, 2]

如果我这样做:Arrays.sort(num)，那么我有:

If I do: Arrays.sort(num), then I have:

name: [Four, Three, One, Two]
num:  [1, 2, 3, 4]

有什么办法可以对 num 进行排序并将其反映在名称中，以便我最终得到:

Is there any way I can possibly do a sort on num and have it reflected in name as well, so that I might end up with:

name: [One, Two, Three, Four]
num:  [1, 2, 3, 4]

?请帮帮我.我想到了比较器和对象，但几乎不了解它们.

? Please do help me out. I thought of Comparators and Objects, but barely know them at all.

推荐答案

你应该以某种方式关联 name 和 num 字段到一个类中然后有该特定类的实例列表.在这个类中，提供一个 compareTo() 方法来检查数值.如果您对实例进行排序，那么名称字段也将按照您想要的顺序排列.

You should somehow associate name and num fields into one class and then have a list of instances of that specific class. In this class, provide a compareTo() method which checks on the numerical values. If you sort the instances, then the name fields will be in the order you desire as well.

class Entity implements Comparable<Entity> {
    String name;
    int num;
    Entity(String name, int num) {
        this.name = name;
        this.num = num;
    }
    @Override
    public int compareTo(Entity o) {
        if (this.num > o.num)
            return 1;
        else if (this.num < o.num)
            return -1;
        return 0;
    }
}

测试代码可能是这样的:

Test code could be like this:

public static void main(String[] args) {
    List<Entity> entities = new ArrayList<Entity>();
    entities.add(new Entity("One", 1));
    entities.add(new Entity("Two", 2));
    entities.add(new Entity("Three", 3));
    entities.add(new Entity("Four", 4));
    Collections.sort(entities);

    for (Entity entity : entities)
        System.out.print(entity.num + " => " + entity.name + " ");
}

输出:

1 => 一个 2 => 两个 3 => 三个 4 => 四

1 => One 2 => Two 3 => Three 4 => Four

这篇关于同时对两个 arrayList 进行排序的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！