java entry-白红宇

java entry

阅读量：6583 次

发布时间：2019-06-24

本文共 1772 字，大约阅读时间需要 5 分钟。

我希望要一个ArrayList<Entry>，类似C++中的pair，

可是Map.Entry是个接口，不能实例化，能够像以下这样写

HashMap
     
       G = new HashMap
      
       ();G.put(1, 9); G.put(4, 6); G.put(2, 8);G.put(3, 7);    ArrayList
       
        
         > arrayList = new         ArrayList
         
          
           (G.entrySet());

ArrayList
     
      
       > arrayList = new     ArrayList
       
        
         >();arrayList.add(new AbstractMap.SimpleEntry(1, 9));

Map
     
       map = new HashMap
      
       ();map.put("d", 2);map.put("c", 1);map.put("b", 1);map.put("a", 3);List
       
        
         > infoIds =    new ArrayList
         
          
           >(map.entrySet());//排序前for (int i = 0; i < infoIds.size(); i++) { String id = infoIds.get(i).toString(); System.out.println(id);}//d 2//c 1//b 1//a 3//排序Collections.sort(infoIds, new Comparator
           
            
             >() { public int compare(Map.Entry
             
               o1, Map.Entry
              
                o2) { //return (o2.getValue() - o1.getValue()); return (o1.getKey()).toString().compareTo(o2.getKey()); }}); //排序后for (int i = 0; i < infoIds.size(); i++) { String id = infoIds.get(i).toString(); System.out.println(id);}//依据key排序//a 3//b 1//c 1//d 2//依据value排序//a 3//d 2//b 1//c 1

List
     
      
       > termls = new ArrayList
       
        
         >();			for(String s: tf.get(i).keySet()) {				termls.add(new AbstractMap.SimpleEntry(s, tf.get(i).get(s)*1.0*Math.log10(count*1.0/df.get(s))));			}			Collections.sort(termls, new Comparator
         
          
           >(){ public int compare(Map.Entry
           
             o1,Map.Entry
            
              o2){ return(o2.getValue().compareTo(o1.getValue())); } } ); System.out.println("line " + (i+1)); for (int ind = 0; ind < termls.size(); ++ind){ System.out.print(termls.get(ind).toString()+" "); } System.out.println();