How to count different elements in Vector using java?

Question

I have a lot of words at hand. What I need to do is to save them and count every different word. The original data may contain some duplicate words.Firstly, I want to use Set, then I can guarantee that I only get the different wrods. But how can I count their times? Is there someone having any "clever" idea?

Answer 1

You can use MultiSet from the Guava library.

http://docs.guava-libraries.googlecode.com/git/javadoc/com/google/common/collect/Multiset.html

Answer 2

You can use Map to solve this problem.

String sample = " I have a problem here. I have a lot of words at hand. What I need to do is to save them and count every different word. The original data may contains duplicate words.Firstly, I want to use Set, then I can guarantee that I only get the different wrods. But how can I count their times? Is there someone having any clever idea?";
    String[] array = sample.split("[\\s\\.,\\?]");
    Map<String,Integer> statistic = new HashMap<String,Integer>();
    for (String elem:array){
        String trimElem = elem.trim();
        Integer count = 0;
        if(!"".equals(trimElem)){
            if(statistic.containsKey(trimElem)){
                count = statistic.get(trimElem);
            }
            count++;
            statistic.put(trimElem,count);
        }
    }

Answer 3

也许您可以使用哈希，在Java中，它可以是HashMap（或HashSet？），您可以哈希每个单词，如果该单词已被哈希，则将与其关联的某个值加1。