如何从特定值枚举哈希表键

Question

例如我有一个Hashtable，我在Double d = 99.22变量中有一个值，在这里我想获取或找到与该值相关的键。

Hashtable<String, Double> balance = new Hashtable<String, Double>();

      balance.put("Zara", new Double(3434.34));
      balance.put("Mahnaz", new Double(123.22));
      balance.put("Ayan", new Double(1378.00));
      balance.put("Daisy", new Double(99.22));
      balance.put("Qadir", new Double(-19.08));

      System.out.println(balance);

      Double d = 99.22;

提前致谢

Answer 1

 Hashtable<String, Double> balance = new Hashtable<String, Double>();

      balance.put("Zara", new Double(3434.34));
      balance.put("Mahnaz", new Double(123.22));
      balance.put("Ayan", new Double(1378.00));
      balance.put("Daisy", new Double(99.22));
      balance.put("Qadir", new Double(-19.08));

      System.out.println(balance);
      Double d = 99.22;



     String key=null;
        for(Map.Entry entry: balance.entrySet()){
          if(d.equals(entry.getValue())){
              key = (String) entry.getKey();
              break;
          }
      }
      System.out.println("got key from value in hashtable key:  "+ key +" value: " + d);    

我希望它会有所帮助。

Answer 2

在帖子中提到的代码段后尝试此代码：

    for(Map.Entry<String, Double> e : balance.entrySet()){
        if(e.getValue()== d.doubleValue()){
            System.out.println(e.getKey());
        }
    }