每当有一个密钥匹配时，添加两个地图的值 [英] Adding values of two maps whenever there is a key match

问题描述

说我有一张地图，如

  {one = 1; 2 = 1;三= 1} 
  

另一个地图如

  {一个= 4; 2 = 4;我知道putAll（）会添加唯一的键并替换现有的键。 
可以添加两个地图，这些地图会产生一个结果，比如在有现有的关键字时添加值。
  {一个= 5; 2 = 5;三= 5} 
  
 
 
解决方案
扩展 HashMap 并覆盖putAll方法。
  public class MyMap extends java.util.HashMap {
 @Override 
 public void putAll（java.util.Map mapToAdd）{
 java.util.Iterator iterKeys = keySet（）。iterator（）; 
 while（iterKeys.hasNext（））{
 String currentKey =（String）iterKeys.next（）; 
 if（mapToAdd.containsKey（currentKey））{
 mapToAdd.put（currentKey，new Integer（Integer.parseInt（get（currentKey）.toString（））+ Integer.parseInt（mapToAdd.get（currentKey ）的ToString（））））; 
} else {
 mapToAdd.put（currentKey，get（currentKey））; 
} 
} 
 super.putAll（mapToAdd）; 
} 
 public static void main（String args []）{
 MyMap m1 = new MyMap（）; 
 m1.put（One，new Integer（1））; 
 m1.put（Two，new Integer（2））; 
 m1.put（Three，new Integer（3））; 
 MyMap m2 = new MyMap（）; 
 m2.put（One，new Integer（4））; 
 m2.put（Two，new Integer（5））; 
 m2.put（Three，new Integer（6））; 
 m1.putAll（m2）; 
 System.out.println（m1）; 
} 
  
} 
 
 
 
现在，创建MyMap的对象而不是HashMap。创建小提琴此处 
 
Say I have a map like 
{one=1; two=1; three=1}
and another map like
{one=4; two=4; three=4}
I know that putAll() would add unique keys and replace existing keys.
Will it be possible to do an addition of both the maps which would produce a result like adding the values whenever there is an existing keyword.
{one=5; two=5; three=5}

解决方案
Extend the HashMap and override the putAll method.
public class MyMap extends java.util.HashMap{
 @Override
 public void putAll(java.util.Map mapToAdd){
      java.util.Iterator iterKeys = keySet().iterator();
      while(iterKeys.hasNext()){
           String currentKey = (String)iterKeys.next();
           if(mapToAdd.containsKey(currentKey)){
                mapToAdd.put(currentKey, new Integer(Integer.parseInt(get(currentKey).toString()) + Integer.parseInt(mapToAdd.get(currentKey).toString())));
           }else{
                mapToAdd.put(currentKey, get(currentKey));
           }
      }
      super.putAll(mapToAdd);
 }
 public static void main(String args[]){
     MyMap m1 = new MyMap();
     m1.put("One", new Integer(1));
     m1.put("Two", new Integer(2));
     m1.put("Three", new Integer(3));
     MyMap m2 = new MyMap();
     m2.put("One", new Integer(4));
     m2.put("Two", new Integer(5));
     m2.put("Three", new Integer(6));
     m1.putAll(m2);
     System.out.println(m1);
 }
}

Now, create objects of MyMap instead of HashMap.  Created a fiddle Here

                        
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