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  • hashMap的遍历

    今天写的一个算法中用到了hashMap,于是将其学习一下

    普通HashMap的遍历

     1 HashMap<String,String> student=new HashMap<String,String>();
     2         student.put("a", "grade 1");
     3         student.put("b", "grade 2");
     4         student.put("c", "grade 3");
     5         Iterator it=student.keySet().iterator();
     6         while(it.hasNext())
     7         {
     8             String m=(String)it.next();
     9             System.out.println("key="+m+" value="+student.get(m));
    10         }
    11         //第二种
    12         Set<Entry<String, String>> sets = student.entrySet();  
    13         for(Entry<String, String> entry : sets) {  
    14             System.out.print(entry.getKey() + ", ");  
    15             System.out.println(entry.getValue());  
    16         }  
    17         //第三种
    18         HashMap<String,Integer> studentScore=new HashMap<String,Integer>();
    19         studentScore.put("a", 98);
    20         studentScore.put("b", 78);
    21         studentScore.put("c", 89);
    22         Iterator iit=studentScore.keySet().iterator();
    23         while(iit.hasNext())
    24         {
    25             String m=(String)iit.next();
    26             System.out.println("key="+m+" value="+studentScore.get(m));
    27         }
    View Code

    含有HashMap的value是ArrayList时

     1 Iterator<Entry<String, ArrayList<TreeNode>>> it = linkedNode.entrySet().iterator();
     2                 while( it.hasNext())
     3                 {
     4                     Map.Entry<String, ArrayList<TreeNode>> entry = it.next();
     5                     String key = entry.getKey();
     6                     ArrayList<TreeNode> values=(ArrayList<TreeNode>)entry.getValue();
     7                     for(TreeNode value:values)
     8                     {
     9                         System.out.print(" name="+value.getName()+" count="+value.getCount());
    10                     }
    11                     System.out.println();
    12                     //TreeNode tempNode= entry.getValue().get(i);
    13                 }
    14                 
    View Code
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  • 原文地址:https://www.cnblogs.com/huicpc0212/p/4346233.html
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