对文本文件中的字符进行计数/排序

本文关键字：排序 字符 文本 文件 | 更新日期: 2023-09-27 17:49:38

我正在尝试编写一个程序，读取文本文件，按字符进行排序，并跟踪每个字符在文档中出现的次数。这是我目前得到的。

class Program
{
    static void Main(string[] args)
    {
        CharFrequency[] Charfreq = new CharFrequency[128];
        try
        {            
        string line;
        System.IO.StreamReader file = new System.IO.StreamReader(@"C:'Users'User'Documents'Visual Studio 2013'Projects'Array_Project'wap.txt");
        while ((line = file.ReadLine()) != null)
        {
            int ch = file.Read();
            if (Charfreq.Contains(ch))
            {
            }     
        }
        file.Close();
        Console.ReadLine();
        }
        catch (Exception e)
        {
            Console.WriteLine("The process failed: {0}", e.ToString());
        }
    }
}

我的问题是，这里的if语句应该包含什么?

我也有一个Charfrequency类，我将在这里包括它，以防它是有帮助的/必要的，我包括它(是的，这是必要的，我使用数组与列表或数组列表)。

public class CharFrequency
{
    private char m_character;
    private long m_count;
    public CharFrequency(char ch)
    {
        Character = ch;
        Count = 0;
    }
    public CharFrequency(char ch, long charCount)
    {
        Character = ch;
        Count = charCount;
    }
    public char Character
    {
        set
        {
            m_character = value;
        }
        get
        {
            return m_character;
        }
    }
    public long Count
    {
        get
        {
            return m_count;
        }
        set
        {
            if (value < 0)
                value = 0;
            m_count = value;
        }
    }
    public void Increment()
    {
        m_count++;
    }
    public override bool Equals(object obj)
    {
        bool equal = false;
        CharFrequency cf = new CharFrequency(''0', 0);
        cf = (CharFrequency)obj;
        if (this.Character == cf.Character)
            equal = true;
        return equal;
    }
    public override int GetHashCode()
    {
        return m_character.GetHashCode();
    }
    public override string ToString()
    {
        String s = String.Format("'{0}' ({1})     = {2}", m_character, (byte)m_character, m_count);
        return s;
    }
}

对文本文件中的字符进行计数/排序

看看这篇文章。

https://codereview.stackexchange.com/questions/63872/counting-the-number-of-character-occurrences

它使用LINQ来实现您的目标

你不应该使用Contains

首先你需要初始化你的Charfreq数组:

CharFrequency[] Charfreq = new CharFrequency[128];
for (int i = 0; i < Charferq.Length; i++)
{
    Charfreq[i] = new CharFrequency((char)i);
}
try

那么你可以

int ch;
// -1 means that there are no more characters to read,
// otherwise ch is the char read
while ((ch = file.Read()) != -1)
{
     CharFrequency cf = new CharFrequency((char)ch);
     // This works because CharFrequency overloads the
     // Equals method, and the Equals method checks only 
     // for the Character property of CharFrequency
     int ix = Array.IndexOf(Charfreq, cf);
     // if there is the "right" charfrequency
     if (ix != -1)
     {
         Charfreq[ix].Increment();
     }     
}
注意这个不是我编写程序的方式。这是使您的程序工作所需的最小更改。

作为旁注，此程序将计算ASCII字符(代码为<= 127的字符)的"频率"

CharFrequency cf = new CharFrequency(''0', 0);
cf = (CharFrequency)obj;

这是一个无用的初始化:

CharFrequency cf = (CharFrequency)obj;

就足够了，否则你创建的CharFrequency只是为了在下一行丢弃它。

字典非常适合这样的任务。您没有说明文件使用的是哪个字符集和编码。因此，由于Unicode非常普遍，我们假设使用Unicode字符集和UTF-8编码。(毕竟，这是。net, Java, JavaScript, HTML, XML，....的默认设置)如果不是这样，那么使用适用的编码读取文件并修复您的代码，因为您目前在StreamReader中使用UTF-8。

下一步是遍历"字符"。然后对字典中"字符"的计数进行递增，就像在文本中看到的那样。

Unicode确实有一些复杂的特性。一种是组合字符，其中基本字符可以用变音符等覆盖。用户将这样的组合视为一个"字符"，或者Unicode称之为字素。值得庆幸的是，. net提供了一个StringInfo类，它将它们作为"文本元素"进行迭代。

所以，如果你仔细想想，使用数组是相当困难的。你必须在你的数组上建立你自己的字典。

下面的示例使用一个Dictionary，并且可以使用LINQPad脚本运行。在它创建字典之后，它排序并转储它，并显示一个漂亮的显示。

var path = Path.GetTempFileName();
// Get some text we know is encoded in UTF-8 to simplify the code below
// and contains combining codepoints as a matter of example.
using (var web = new WebClient())
{
    web.DownloadFile("http://superuser.com/questions/52671/which-unicode-characters-do-smilies-like-%D9%A9-%CC%AE%CC%AE%CC%83-%CC%83%DB%B6-consist-of", path); 
}
// since the question asks to analyze a file
var content = File.ReadAllText(path, Encoding.UTF8); 
var frequency = new Dictionary<String, int>();
var itor = System.Globalization.StringInfo.GetTextElementEnumerator(content);
while (itor.MoveNext()) 
{
    var element = (String)itor.Current;
    if (!frequency.ContainsKey(element)) 
    {
        frequency.Add(element, 0);
    }
    frequency[element]++;
}
var histogram = frequency
    .OrderByDescending(f => f.Value)
    // jazz it up with the list of codepoints in each text element
    .Select(pair =>  
        {
            var bytes = Encoding.UTF32.GetBytes(pair.Key);
            var codepoints = new UInt32[bytes.Length/4];
            Buffer.BlockCopy(bytes, 0, codepoints, 0, bytes.Length);
            return new { 
                Count = pair.Value, 
                textElement = pair.Key, 
                codepoints = codepoints.Select(cp => String.Format("U+{0:X4}", cp) ) };
        });
histogram.Dump(); // For use in LINQPad
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