Question

我有一个包含HashMap作为值的HashMap。我想将一个密钥对值添加到被视为值的HashMap中。我写了这样的东西

HashMap<String, HashMap<String, Integer>> record= new HashMap<>();
record.put("John",....)// I am not sure what to put here

怎么办呢？

Answer 1

//get innerMap using key for record map
innerMap = record.get("John");
if(innerMap == null){ // do not create new innerMap everyTime, only when it is null
   innerMap = new HashMap<String, Integer>();
}
innerMap.put("Key", 6); // put using key for the second/inner map
record.put("John", innerMap)

Answer 2

所以，那个值必须像这样存储：

HashMap<String,Integer> value = new HashMap<>();
value.put("Your string",56);

然后将此值Hashmap添加到您的记录哈希映射中，如下所示：

record.put("John",value);

Answer 3

HashMap<String, HashMap<String, Integer>> record= new HashMap<>();
HashMap hm = new HashMap<>();
hm.put("string", 1);
record.put("John", hm);

Answer 4

首先，您必须获取HashMap的实例

HashMap<String, Integer> map = new HashMap<>();
map.put("key", 1);

然后

recore.put("John", map);

Answer 5

You can use like this -

 HashMap<String, HashMap<String, Integer>> record= new HashMap<String, HashMap<String, Integer>>();

    HashMap<String, Integer> subRecord = new HashMap<String, Integer>();
    subRecord.put("Maths", 90);
    subRecord.put("English", 85);

    record.put("John",subRecord);

Answer 6

如果您需要有关如何从内部Hashmap获取值的信息，我已经看到了很多答案。请参阅此内容。

    HashMap<String, HashMap<String, Integer>> record= new HashMap<>();
    Map<String, Integer> innerMap = new HashMap<String, Integer>();    
    innerMap.put("InnerKey1", 1);
    innerMap.put("InnerKey2", 2);

将值存储到外部Hashmap

   record.put("OuterKey", innerMap);

这是检索值的方法

  Map<String, Integer> map = record.get("OuterKey");
  Integer myValue1 = map.get("InnerKey1");
  Integer myValue2 = map.get("InnerKey2");

在HashMap中将元素添加到HashMap中

6 个答案: