问题描述
<块引用>可能的重复:
如何对地图进行排序<键、值>关于 Java 中的值?
在我的项目中，我采用了这样的 HashMap
<块引用>HashMap 度数 = new HashMap();
假设我有:
degree.put("a",5);度.put("b",2);度.put("c",4);度.put("d",2);度.put("e",3);度.put("f",5);<块引用>
现在我必须根据给定的整数值对该列表进行排序
排序后的 HashMap 应该是:
<块引用>{a=5, f=5, c=4, e=4, b=4, d=2}
我该怎么做?
一个 HashMap 是一个 无序 集合.它没有排序顺序.即使是 TreeMap 也会按键排序，而不是按值排序.
如果要按值的排序顺序准备排序列表，则必须创建一个适当的对象，例如 ArrayList<Map.Entry<String,Integer>>，遍历您的 HashMap 并插入所有条目，然后使用排序函数调用 Collections.sort.
Possible Duplicate:
How to sort a Map<Key, Value> on the values in Java?
In my project, I have taken a HashMap like this
HashMap degree = new HashMap();
Suppose I have:
degree.put("a",5);
degree.put("b",2);
degree.put("c",4);
degree.put("d",2);
degree.put("e",3);
degree.put("f",5);
Now I have to Sort this list according to given Integer values
Sorted HashMap Should be :
{a=5, f=5, c=4, e=4, b=4, d=2}
How I can do this ?
A HashMap is an unordered collection. It has no sort order. Even a TreeMap will sort by key, not value.
If you want to prepare a sorted list by the sort order of the values, you'll have to create an appropriate object, such as an ArrayList<Map.Entry<String,Integer>>, iterate over your HashMap and insert all the entries, and then call Collections.sort with a collation function.
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