问题描述
好的，这是一个棘手的问题.我有一个集合列表.我想按顺序对集合中的对象进行排序.
Ok this is a tricky one. I have a list of Sets. I would like to sort the objects in the Sets in an order.
将每个集合想象成代表学校的一个班级.每个集合都包含人员对象.一个人对象持有一个字符串值作为名称.我想在循环并写出之前按名称排列 Set 中的 Persons.
Imagine each set as repressenting a class in a school. Each set contains person objects. A person object holds a String value for name. I'd like to arrange the Persons in the Set by name before I loop through and write them out.
有没有办法使用 Collections.sort(); 或类似的东西来实现这一点?
Is there anywahy to use Collections.sort(); or something similar to achieve this?
for (Set<Person> s : listOfAllChildren) {
for (Person p : s) {
if(p.getClass().equalsIgnoreCase("Jones")){
System.out.println(p.getName());
}
else if...//carry on through other classes
}
}
我知道一个班有 2 个以上的孩子可能有相同的名字，但请忽略这个
推荐答案
一个 Set 没有 ordering 的概念，因为它是一个集合.
A Set has no notion of ordering because, well, it's a set.
TreeSet 类实现的SortedSet 接口可以使用.只需向构造函数提供适当的 Comparator，或让您的 Person 类实现 Comparable.
There is a SortedSet interface implemented by TreeSet class that you can use. Simply provide an appropriate Comparator to the constructor, or let your Person class implements Comparable.
这篇关于按所有对象包含的字符串值对 Set 中的对象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跟版网！