Question

我正在尝试计算文本文件中每个单词的出现次数（不区分大小写）并将单词及其计数存储在列表中。

这是我要存储在列表中的每个单词的对象类，

public class WordItem
{
    public string Word { get; set; }
    public int Count { get; set; }
}

和我的代码函数解析文本文件

public List<WordItem> FindWordCount()
{
    //I've successfully parsed the text file into a list
    //of words and stripped punctuation up to this point
    //and stored them in List<string> wordlist.

    List<string> wordlist;
    List<WordEntry> entries = new List<WordEntry>();

    foreach (string word in wordlist)
    {
        WordItem temp = new WordItem();
        temp.Word = word;
        temp.Count = 1;
        entries.Add(temp);
    }
}

我如何编辑单词计数功能以防止列表中出现重复单词，而是每当我再找一个单词时增加计数值？

Answer 1

我会使用Dictionary和不区分大小写的字符串比较器：

public IEnumerable<WordItem> FindWordCount(IEnumerable<string> wordlist)
{
    var wordCount = new Dictionary<string, int>(StringComparer.CurrentCultureIgnoreCase);
    foreach (string word in wordlist)
    {
        int count = 0;
        bool contained = wordCount.TryGetValue(word, out count);
        count++;
        wordCount[word] = count;
    }
    foreach (var kv in wordCount)
        yield return new WordItem { Word = kv.Key, Count = kv.Value };
}

您可以这样使用它：

var wordList = new string[] { "A", "a", "b", "C", "a", "b" };
var wordCounts = FindWordCount(wordList).ToList();

Answer 2

还有很好的单线解决方案：

IEnumerable<WordItem> countedList = wordlist.Distinct().Select(word => new WordItem() { Word = word, Count = wordlist.Count(compWord => word.Equals(compWord, StringComparison.InvariantCultureIgnoreCase)) });

或者，如果您更喜欢字典，以便以后能够搜索特定单词：

Dictionary<string, int> dictionary = wordlist.Distinct().ToDictionary<string, string, int>(word => word, word => wordlist.Count(compWord => word.Equals(compWord, StringComparison.InvariantCultureIgnoreCase)));

性能当然比Tim Smelters解决方案少一点，因为Count（） - Call（导致O(n^2)）但使用C# 6.0你可以写下方法使用lambda表达式来定义而不是正文。

Answer 3

简单且适合您的类型：

public string[] wordList;

public class WordItem
{
    public string Word { get; set; }
    public int Count { get; set; }
}

public IEnumerable<WordItem> FindWordCount()
{
  return from word in wordList
         group word by word.ToLowerInvariant() into g
         select new WordItem { Word = g.Key, Count = g.Count()};
}

如何跟踪文本文件中的字数

3 个答案: