计算地图中出现的价值

问题描述

我有以下类型的地图:

private HashMap<Integer, HashMap<String, Object>> entireMap;

键从1到n.wholeMap内的subMap具有以下类型:

The keys go from 1 - n. The subMap inside the entireMap is of the following type:

HashMap<String, Object> subMap = new HashMap<String, Object>();

整个地图的每个键都包含此subMap(以及更多):

Every key of the entire map contains this subMap (and a lot more):

subMap.put("user_name", usid[1]);

所以我最后有这样的东西:

So i have something like this at the end:

{1 {"user_name" = "Arthur", "otherKeys = ..."}}
{2 {"user_name" = "Bela", "otherKeys = ..."}}
{3 {"user_name" = "Ceasar", "otherKeys = ..."}}
{4 {"user_name" = "Ceasar", "otherKeys = ..."}}
{5 {"user_name" = "Bela", "otherKeys = ..."}}
{6 {"user_name" = "Bela", "otherKeys = ..."}}

现在，我想计算整个地图中user_name的最大出现次数，在这种情况下，它将是3(重复出现3次).

Now I want to count the max occurence of a user_name in the entireMap, in this case it would be 3 (bela occures three times).

我该怎么做?

推荐答案

以下是实现示例.

注意:请勿在生产代码中使用此类地图初始化！

Note: don't use such map initialization in production code!

    HashMap<Integer, HashMap<String, Object>> entireMap = new HashMap<>();
    entireMap.put(1, new HashMap<String, Object>() {{
        put("user_name", "Arthur");
        put("other_key1", "val");
        put("other_key2", "val");
    }});
    entireMap.put(2, new HashMap<String, Object>() {{
        put("user_name", "Bela");
        put("other_key2", "val");
    }});
    entireMap.put(3, new HashMap<String, Object>() {{
        put("user_name", "Ceasar");
    }});
    entireMap.put(4, new HashMap<String, Object>() {{
        put("user_name", "Ceasar");
    }});
    entireMap.put(5, new HashMap<String, Object>() {{
        put("user_name", "Bela");
    }});
    entireMap.put(6, new HashMap<String, Object>() {{
        put("user_name", "Bela");
    }});

    Map<Object, Long> result = entireMap
            .values()
            .stream()
            .map(map -> map.get("user_name"))
            .collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));

    System.out.println(result);

    Long max = Collections.max(result.values());
    System.out.println(max);

输出:

{Ceasar=2, Arthur=1, Bela=3}
3

这篇关于计算地图中出现的价值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！