Thread: Sorting by numbers of words in each sentence that is in ArrayList index.

Hello! I am a beginner!I have a task to sort sentences by its word quantity, that is in Arraylist.For example,here is the code of my Array example:

List<String> numberOfWords=new ArrayList<>();

numberOfWords.add("Happy coding!"); //2 words or 3 with(!),I don't know
numberOfWords.add("He plays football in the playground everyday"); //7
numberOfWords.add("She is cooking an omellette"); //5
numberOfWords.add("I am coding in Java"); //5
numberOfWords.add("I want to code very well"); //6

// And the result must be like this: So, please could anyone give me some advice on how to come to this outcome??? Thanks!!!

Happy coding! //2 words
I am coding in Java //5 words
She is cooking an omellette //5words
I want to code very well //6 words
He plays football in the playground everyday //7words

You need to write Comparator for your sentences, which compares strings by the number of words (or spaces) in them - to measure number of words you can use String.replaceAll("\\S", "!").replaceAll("\\s", "") to replace all words with exclamation marks and remove spaces - so that length of the result equals to number of words.

Then you can simply call Collections.sort() and pass your list and your comparator here.

You can use code formatting and/or highlight tags to make your posted code look "pretty" rather than doing the formatting yourself. You can learn more about that in the Announcement topic at the topic of the sub-forum with other useful info for new comers.

Did you notice that the number of words is the number of spaces + 1? Maybe you could use that with a String method somehow. Review the String API and the existing methods to see if you get any ideas.

Based on all your recomendations, I wrote this code but I can't find what's wrong with that?Please, look and point at my mistakes! There are no fatal errors, just the result isn't correct, not that I wanted !The order of the sentences isn't correct!

int i = 0;
        String words=null;
 
        for (i = 0; i < numberOfWords.size(); i++) {
            words = numberOfWords.get(i).replaceAll("[a-zA-z]", "!").replaceAll("\\s*", "");
            Collections.sort(numberOfWords, new SortingSentence());
            System.out.println(numberOfWords.get(i));
        }
    }
 
    @Override
    public int compare(String t, String t1) {
        if (t.length() > t1.length()) {
            return 1;
        } else if (t.length() < t1.length()) {
            return -1;
        } else {
            return 0;
        }
    }
}