how can I verify if an String is already in a hashtable? java

Question

I have the following case: I'm trying to loop over an ArrayList and compare every element to an HashTable . If the elements (string) are equal, I want to copy that in a new HashTable neu . Until here it goes well. But I want, that if the word is already in the new HashTable neu , to not put it again and simple add one count to the value which represents the frequency. I suppose that the else-block is never reached in this code, because test output it's never displayed. I know that until contentEquals it works well, there it returns me all words which are equal.

So: how can I verify if an String is already in a HashTable ? I hope it's not duplicated, I have seen a lot of similar questions but didn't know how to use it correctly for my code.

Hashtable<String, Long> neu = new Hashtable<String, Long>();
ArrayList<String> words = new ArrayList<String>();
Hashtable<String, Long> count = new Hashtable<String, Long>();

// adding input

for (String s : count.keySet()) { 

    for (String x : words) {
            if (x.contentEquals(s)) {  
                if (!neu.containsKey(s)) {  
                    neu.put(s, (long) 1);
                } else { 
                    long p = neu.get(s); 
                    p = p + 1;
                    neu.put(s, p);
                    System.out.println("test");
                }
            }
        }

The Input is the following: For count:

        try {
        BufferedReader in = new BufferedReader(new FileReader(
                "griechenland_test.txt"));
        String str;

        while ((str = in.readLine()) != null) {
            str = str.toLowerCase(); // convert to lower case
            String[] words = str.split("\\s+"); // split the line on
                                                // whitespace, would return
                                                // an array of words

            for (String word : words) {
                if (word.length() == 0) {
                    continue;
                }

                Long occurences = wordcount.get(word);

                if (occurences == null) {
                    occurences = (long) 1;
                } else {
                    occurences++;
                }

                count.put(word, occurences);
            }

        }

for words:

        BufferedReader br = new BufferedReader(new FileReader("outagain.txt")); 
for (String line = br.readLine(); line != null; line = br.readLine()) {
        String h[] = line.split("   ");

        words.add(h[0].toString());

    }

Answer 1

Use the containsKey() method to check if the given key is already in the hashtable.

static Hashtable<String, Long> map = new Hashtable<String, Long>();

    public static void main(String[] args)
    {
        map.put("test", 1l);

        System.out.println(map.containsKey("test")); // true
    }

For string comparison, either use the equals(Object) or equalsIgnoreCase(String) method.

So your code should look like this...

for (String s : count.keySet())
        {
            for (String x : words)
            {
                if (x.equals(s))
                    neu.put(s, neu.containsKey(s) ? neu.get(s) + 1 : 1l);
            }
        }

Please verify the content of your words and count . This should be the issue, because your code is working fine.

Answer 2

I could manage it! I supposed the fault was really the way from input, there where no duplicateds, for that reason the "else" was never reached! I just eliminate that condition and changed a bit the structure. Thanks anyway all for your effort! :)

for (String x : hash.keySet()) {
        long neu = hash.get(x);
        for (String s : words) {
            if (x.equals(s)) {
                neuS.add(x);
                neuZ.add(neu);
                disc = disc + 1;
            }
        }
    }