在Java中编写模式方法以查找数组中最不频繁出现的元素

Question

我有字符串的arraylist，有类似这样的数据 { “这个”， “是”，是”， “重复”}

我需要一个java代码，它会给我最少重复的元素

输出应该是 这个= 1 重复= 1

提前致谢

Answer 1

这样就可以了，这有点长，但也许还有一些类似的工具包可以做同样的事情（到目前为止还没找到）：

    String[] words = {"this", "is", "is", "repeating"};

    TreeMap<Integer, List<String>> frequencyMap = new TreeMap<Integer, List<String>>();
    for (String word : words) {
        Integer frequency = 0;
        for (String word2 : words) {
            if (word.equals(word2)) {
                frequency++;
            }
        }

        if (frequencyMap.containsKey(frequency)) {
            List<String> wordsWithFrequency = frequencyMap.get(frequency);
            wordsWithFrequency.add(word);
        } else {
            List<String> wordsWithFrequency = new ArrayList<String>();
            wordsWithFrequency.add(word);
            frequencyMap.put(frequency, wordsWithFrequency);
        }
    }

    if (frequencyMap.size() > 0) {
        List<String> leastFrequentWords = frequencyMap.get(frequencyMap.firstKey());
        for (String string : leastFrequentWords) {
            System.out.println(string + " = " + frequencyMap.firstKey());
        }
    }

打印出来：

this = 1
repeating = 1