我有一个像这样的三元组的hashmap:
HashMap<String, List<Triplet<String,Integer,Integer>>> output = new HashMap<String, List<Triplet<String,Integer,Integer>>>();
其中密钥是文件名,三元组包含单词及其频率信息(tf和df)的信息。
{File1 = {coffee,23,1},{caffeine,12,2},{brew,9,1}; File2 = {}.......}
我想根据三元组的第二个值(即术语频率)对这个三元组列表的值进行排序。
for (Entry<String, List<Triplet<String, Integer, Integer>>> entry : output.entrySet()) {
String key = entry.getKey();
List<Triplet<String, Integer, Integer>> value = entry.getValue();
接下来会发生什么?
这是Triplet的样子:
public class Triplet<T, U, V> {
private final T first;
private final U second;
private final V third;
public Triplet(T first, U second, V third) {
this.first = first;
this.second = second;
this.third = third;
}
public T getFirst() {
return first;
}
public U getSecond() {
return second;
}
public V getThird() {
return third;
}
}
任何帮助,指导将不胜感激。
我想到的方法有两种:
Triplet
Comparable
Comparator
您可以对列表进行排序或使用例如一个TreeSet
如果你不能通过在它上面实现Triplet
来改变你的Comparable
类,这将是一个解决方案,使用Collections.sort
方法:
for (Entry<String, List<Triplet<String, Integer, Integer>>> entry : output.entrySet()) {
String key = entry.getKey();
List<Triplet<String, Integer, Integer>> value = entry.getValue();
// This sorts the list using the anonymous instantiated Comparator class
Collections.sort(value, new Comparator<Triplet<String, Integer, Integer>>(){
@Override
public int compare(Triplet<String, Integer, Integer> object1, Triplet<String, Integer, Integer> object2) {
return object1.getSecond().compareTo(object2.getSecond());
}
});
或者,以更通用的方式,不使用硬类型:
Collections.sort(value, new Comparator<Triplet>(){
@Override
public int compare(Triplet object1, Triplet object2) {
return object1.getSecond().compareTo(object2.getSecond());
}
});
那这个呢?
public class Triplet<T, U, V> implements Comparable<Triplet<T, U, V> > {
private final T first;
private final U second;
private final V third;
public Triplet(T first, U second, V third) {
this.first = first;
this.second = second;
this.third = third;
}
public T getFirst() {
return first;
}
public U getSecond() {
return second;
}
public V getThird() {
return third;
}
public int compareTo(Triplet<T, U, V> comparetrpl) {
T a = comparetrpl.getFirst();
//ascending order
return (this.first > a) ? 1 : 0;
//descending order
//return (a > this.first) ? 1 : 0;
}
}
并使用sort
方法?