Solved

How to Reverse HashMap, key becomes values and vice-versa

Posted on 2003-11-06
4
2,499 Views
Last Modified: 2010-07-27
I have a HashMap with key-values. Sometime, I need to know key for a given value. Could anyone let me know how to do that ?
0
Comment
Question by:vinay_delhi
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
4 Comments
 
LVL 3

Accepted Solution

by:
applekanna earned 50 total points
ID: 9692804
import java.util.*


  HashMap h = new HashMap();
     Iterator i = h.entrySet().iterator();
     while(i.hasNext())
     {
      Map.Entry entry = (Map.Entry)i.next();
     System.out.println(entry.getKey() + "/" + entry.getValue());
   //  if((Object) entry.getValue() == your code to compare
     }
0
 
LVL 3

Expert Comment

by:applekanna
ID: 9692813
Assuming you have string for both key and value
     {
      Map.Entry entry = (Map.Entry)i.next();
     System.out.println(entry.getKey() + "/" + entry.getValue());
     String key =  (String) entry.getValue()
     String value = (String) entry.getValue();
   //  if(value.equals("some")
     }
0

Featured Post

Get 15 Days FREE Full-Featured Trial

Benefit from a mission critical IT monitoring with Monitis Premium or get it FREE for your entry level monitoring needs.
-Over 200,000 users
-More than 300,000 websites monitored
-Used in 197 countries
-Recommended by 98% of users

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

After being asked a question last year, I went into one of my moods where I did some research and code just for the fun and learning of it all.  Subsequently, from this journey, I put together this article on "Range Searching Using Visual Basic.NET …
Java contains several comparison operators (e.g., <, <=, >, >=, ==, !=) that allow you to compare primitive values. However, these operators cannot be used to compare the contents of objects. Interface Comparable is used to allow objects of a cl…
Viewers learn how to read error messages and identify possible mistakes that could cause hours of frustration. Coding is as much about debugging your code as it is about writing it. Define Error Message: Line Numbers: Type of Error: Break Down…
The viewer will learn how to implement Singleton Design Pattern in Java.

726 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question