Saturday, November 15, 2008

Sorting Dictionary object in .Net

A few days ago I came across a sorting-dictionary problem at work. The easiest way to have a sorted dictionary in .Net is to use the SortedDictionary(TKey, TValue) item. Every time you enter a keyvaluepair in the SortedDictionary item, it will be sorted automatically.

But I had to sort an existing Dictionary(TKey, TValue) item, that was provided by some other program. Initially, I was hoping that there is some Dictionary.Sort() function available that I could use but there isn't.

After some research I found that you could use the List.Sort() function to sort the dictionary by keys. But that is not all. You also need to add a delegate in the List.Sort() function to carry out the sorting process.

Here is the code.

//Code takes a Dictionary<double,int> item, sorts it and return the new Dictionary<double,int> item

private static Dictionary<double,int> Sort(Dictionary<double,int> Dict)
//Create a List object from the Dictionary item
List<keyvaluepair<double,int>> result = new List<keyvaluepair<double,int>>(Dict);

//Use the delegate in the List.Sort function to compare the keys for sorting
KeyValuePair<double, int> first,
KeyValuePair<double, int> second)
return first.Key.CompareTo(second.Key);

//Add the List items into a new dictionary item
Dictionary<double,int> sortedDict = new Dictionary<double,int>();

foreach (KeyValuePair<double, int> kvp in result)

double key = kvp.Key;
int value = kvp.Value;

sortedDict.Add(key, value);

return sortedDict;

If there is a better way to achieve this, please let me know.

Tuesday, September 9, 2008

New Semester, New Challenges

The stint at ESRI ended this august. The Fall'08 semester has started and I have already started to wish that humans didn't have to sleep. Distributed Computing and Information Retrieval will be my focus of study this fall. While I like the Distributed Computing course and the technology that we will use :WCF, I am more excited about IR. Hope this will be an amazing learning experience.

Tuesday, April 29, 2008

Internship @ ESRI

I have been hunting for internships for a while. Due to the course load and other mundane activities I started my hunt a little late and hence was always under the impression that probably its too late now. But some companies contacted me and finally I got a full-time summer internship offer from ESRI . I am really excited about that and I hope that it will be one rewarding and learning experience.

Sunday, February 17, 2008

IR or Spam Filter

I haven't been updating my blog lately. The commencement of the spring 2008 semester has to do something with that but the real reason is that I have been busy researching some interesting topics for my AI project.

Last semester I wanted to create an Image Spam Filter for my "Data mining & Pattern Recognition" class. My theory was to apply OCR techniques to capture text from the image, after which it really becomes a text spam-filter problem. I was thinking of using Neural Networks for Image Text recognition and Bayes' Theorem for spam-filtering. But my idea was unanimously rejected by my group and instead we developed a Handwriting Recognition system (which was still a better project to work on than our previous plan to tell time by reading an image of analogue clock.)

So now I have a chance to have another go at my Image Spam Filter project. But I am still debating about it. The reason is that I am also fond of Information Retrieval problems. I am thinking of working on a Search engine and automatic indexing of a technical book/manual. Since this is an individual project I can do whatever I want (Of course my professor has to approve it.)

If I think about it, I find both, IR and Spam Filter, interesting. So it is not a clash of interest but more of what will I gain from them and what I want to do in future.

While I try to analyze this, feel free to give me your suggestions. Maybe you can give me an insight which may eventually help me reach a decision.