双除法的错误行为

我有一个HashMap called List<String, Intger> wordFreqMap whose size is 234

wordFreqMap = {radiology=1, shift=2, mummy=1, empirical=1, awful=1, geoff=1, .......}

我想计算term frequency每个词的。

term frequency = frequency of term / total number of terms

public static Map<String, Double> getTFMap (Map<String, Integer> wordFreqMap)
    {
        Map<String, Double> tfMap = new HashMap<String, Double>();
        int noOfTerms = wordFreqMap.size();
        Double tf;

        for (Entry<String, Integer> word : wordFreqMap.entrySet() ) 
        {
                tf = (double) ( word.getValue() / noOfTerms );
                tfMap.put(word.getKey(), tf );
        }
        return tfMap;
    }

我的问题是，tfMap正在返回{radiology=0.0, shift=0.0, mummy=0.0, empirical=0.0, awful=0.0, geoff=0.0, .....}

我不明白为什么它会返回0.0每个学期。我如何解决它？

我应该得到类似的东西{radiology=0.00427, shift=0.00854, ...}

您正在执行整数除法，然后进行类型转换：

tf = (double) ( word.getValue() / noOfTerms );
                ^-----integer division----^

对除法中的元素之一进行类型转换以转换为浮点除法：

tf = ((double)word.getValue()) / noOfTerms;