双师行为错误 [英] Double division behaving wrongly

问题描述

我有一个 HashMap 调用列表< String，Intger> wordFreqMap 其大小是 234

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

我想计算每个单词的术语频率。

 术语频率=术语频率/总词数
 
 public static Map< String，Double> ; getTFMap（Map< String，Integer> wordFreqMap）
 {
 Map< String，Double> tfMap = new HashMap< String，Double>（）; 
 int noOfTerms = wordFreqMap.size（）; 
双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，.....} / p>

我不明白为什么它为每个术语返回 0.0 。我应该如何解决？

我应该得到一些类似 {radiology = 0.00427，shift = 0.00854，...}

解决方案

您正在执行一个整数除法，然后键入cast：

  tf =（double）（word.getValue（）/ noOfTerms）; 
 ^ -----整数除法---- ^ 
  

分区中的元素转换成浮点除法：

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

I have a HashMap called List<String, Intger> wordFreqMap whose size is 234

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

I want to calculate the term frequency of each word.

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;
    }

My problem is that, tfMap is returning {radiology=0.0, shift=0.0, mummy=0.0, empirical=0.0, awful=0.0, geoff=0.0, .....}

I don't understand why it returns 0.0 for every term. How do I fix it?

I should get something like {radiology=0.00427, shift=0.00854, ...}

解决方案

You're performing an integer division and then type casting:

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

Type cast one of the elements in the division to convert into a floating point division:

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

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