Iterating through a HashMap

Question

Hi!
I am trying to iterate through a HashMap that stores the 2 length words as keys and their number of occurrence in the given text. What I want to do is to count the total number of 2letter words which starts with the same letter. Unfortunately I could not find the code that will compare the 2 adjacent keys. I can take the next entry with Map.Entry meNext = (Map.Entry)iter.next(); but I cannot take the current entry with Map.Entry me = (Map.Entry)iter;. Or the next next entry.
I hope I am clear. I would be really glad for your advices. Below is my code, which gives error:
java.lang.ClassCastException: java.util.HashMap$EntryIterator cannot be cast to java.util.Map$Entry
Iterator iter=symbols.entrySet().iterator();
          while (iter.hasNext()) {
               Map.Entry me = (Map.Entry)iter;
               Map.Entry meNext = (Map.Entry)iter.next();
               String valueToString = (me.getValue()).toString();
               String valueToStringNext = (meNext.getValue()).toString();
               String keyToString = (me.getKey()).toString();
               String keyToStringNext = (meNext.getKey()).toString();
               int numberOfElements = (int)Integer.valueOf(valueToString).intValue();
               while (keyToString.substring(0,1).equals(keyToStringNext.substring(0, 1))) {
                          numberOfElements += (int)Integer.valueOf(valueToStringNext).intValue();
          }

Answer 1

thanks a lot for your answer yawmark, but I think I really need to take and compare the 2 adjacent key entries of the hashmap. because later on if the userchoice=2gram, I want to calculate the probability of the 2nd char given the first char. i.e. Prob(b when given a)=numberof(ab) / numberof(words starting with a), otherwise it calculates the probability of the word. i.e. Prob(ab) = numberof(ab) / numberof(all words in the document)
so length in the code = number of all words in the doc.
I have my hashmap in sorted, so all the words starting with the same letter will be next to each other. So it can count until it sees another starting letter in the next word.
The output should be the contents of the probability hashmap, which contains <entries of symbols hashmap which are <words,occurances>, probability of the words>
for ex. (in this ex it just calculates the probability = occurance/numberof all words.
&#12362;&#12452;=2=0.5
&#12452;&#12403;=1=0.25
&#12403;&#12362;=1=0.25
for the document: &#12362;&#12452;&#12403;&#12362;&#12452;
          Iterator iter=symbols.entrySet().iterator();
          while (iter.hasNext()) {
               Map.Entry me = (Map.Entry)iter;
               Map.Entry me = (Map.Entry)iter.next();
               String valueToString = (me.getValue()).toString();
               String valueToStringNext = (meNext.getValue()).toString();
               String keyToString = (me.getKey()).toString();
               String keyToStringNext = (meNext.getKey()).toString();
               int numberOfElements = (int)Integer.valueOf(valueToString).intValue();
               while (keyToString.substring(0,1).equals(keyToStringNext.substring(0,1))) {
                          numberOfElements += (int)Integer.valueOf(valueToStringNext).intValue();
               if(userChoice.equals("2gram")) {
                    probability.put(me, ((double)Double.valueOf(valueToString).doubleValue()) / numberOfElements);
               else
               probability.put(me, ((double)Double.valueOf(valueToString).doubleValue()) / length);
          }Edited by: koksalasli on Dec 21, 2009 3:06 PM