您好,我正在使用以下代码对我的 HashMap 进行排序,它对映射进行了正确排序,但不计算重复值,
Map<String, Integer> mymap = new HashMap<String, Integer>();
mymap.put("item1", 5);
mymap.put("item2", 1);
mymap.put("item3", 7);
mymap.put("item4", 1);
Map<String, Integer> tempMap = new HashMap<String, Integer>();
for (String wsState : mymap.keySet()) {
tempMap.put(wsState, mymap.get(wsState));
}
List<String> mapKeys = new ArrayList<String>(tempMap.keySet());
List<Integer> mapValues = new ArrayList<Integer>(tempMap.values());
HashMap<String, Integer> sortedMap = new LinkedHashMap<String, Integer>();
TreeSet<Integer> sortedSet = new TreeSet<Integer>(mapValues);
Object[] sortedArray = sortedSet.toArray();
int size = sortedArray.length;
for (int i = 0; i < size; i++) {
sortedMap.put(mapKeys.get(mapValues.indexOf(sortedArray[i])),
(Integer) sortedArray[i]);
}
for (Map.Entry<String, Integer> entry : mymap.entrySet())
System.out.println("Item is:" + entry.getKey() + " with value:"
+ entry.getValue());
System.out.println("***");
for (Map.Entry<String, Integer> entry : sortedMap.entrySet())
System.out.println("Item is:" + entry.getKey() + " with value:"
+ entry.getValue());
结果如下(item 4没有显示,因为它的值和item2的一样!!!):
Item is:item4 with value:1
Item is:item2 with value:1
Item is:item3 with value:7
Item is:item1 with value:5
***
Item is:item2 with value:1
Item is:item1 with value:5
Item is:item3 with value:7
它是一个HashMap,需要按值排序。 预期输出是:
Item is:item3 with value:7
Item is:item1 with value:5
Item is:item2 with value:1
Item is:item4 with value:1
或
Item is:item2 with value:1
Item is:item4 with value:1
Item is:item1 with value:5
Item is:item3 with value:7
最佳答案
您正在使用 TreeSet<Integer> sortedSet
SETS 根据定义不允许重复。
这是一个按值排序的示例,正如您所期望的那样,不会丢失任何条目。
import java.util.*;
public class Test {
public static Map<String, Integer> sortByValueDesc(Map<String, Integer> map) {
List<Map.Entry<String, Integer>> list = new LinkedList(map.entrySet());
Collections.sort(list, new Comparator<Map.Entry<String, Integer>>() {
@Override
public int compare(Map.Entry<String, Integer> o1, Map.Entry<String, Integer> o2) {
return o2.getValue().compareTo(o1.getValue());
}
});
Map<String, Integer> result = new LinkedHashMap<>();
for (Map.Entry<String, Integer> entry : list) {
result.put(entry.getKey(), entry.getValue());
}
return result;
}
public static void main(String[] args) {
HashMap<String, Integer> map = new HashMap<String, Integer>();
map.put("item1", 1);
map.put("item2", 2);
map.put("item3", 1);
map.put("item4", 7);
map.put("item5", 3);
map.put("item6", 4);
for (Map.Entry<String, Integer> entry : map.entrySet()) {
System.out.println("Item is:" + entry.getKey() + " with value:"
+ entry.getValue());
}
System.out.println("*******");
Map<String,Integer> sortedMap = sortByValueDesc(map);
for (Map.Entry<String, Integer> entry : sortedMap.entrySet()) {
System.out.println("Item is:" + entry.getKey() + " with value:"
+ entry.getValue());
}
}
}
我得到的结果是(现在我检查你想要更大的值是第一个):
Item is:item4 with value:7
Item is:item2 with value:2
Item is:item3 with value:1
Item is:item1 with value:1
Item is:item6 with value:4
Item is:item5 with value:3
*******
Item is:item4 with value:7
Item is:item6 with value:4
Item is:item5 with value:3
Item is:item2 with value:2
Item is:item3 with value:1
Item is:item1 with value:1
为什么你在这里丢失一个元素是你的问题:
//HERE YOU ARE GETTING ALL THE VALUES
List<Integer> mapValues = new ArrayList<Integer>(tempMap.values());
HashMap<String, Integer> sortedMap = new LinkedHashMap<String, Integer>();
//YOU ARE INSERTING THE VALUES TO A TreeSet WHICH WILL REMOVE DUPLICATES
TreeSet<Integer> sortedSet = new TreeSet<Integer>(mapValues);
关于java - 对具有重复值的 HashMap 进行排序,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/12738216/