FileReader类在C#

Question

我正在寻找快速类为工作文本文件和舒适的阅读不同的对象(方法，如NextInt32,NextDouble,NextLine等)。可你建议我的东西吗？

编辑： BinaryReader是坏类在我的情况。格式的数据不是二进制的。我有文件一样

1 2 3
FirstToken NextToken
1.23 2,34

我想读这个文件代码，如：

int a = FileReader.NextInt32();
int b = FileReader.NextInt32();
int c = FileReader.NextInt32();
int d = FileReader.NextString();
int e = FileReader.NextString();
int f = FileReader.NextDouble();
int g = FileReader.NextDouble();

Edit2: 我是在寻找模扫描仪自Java

Answer 1

我要添加这样一个单独的答案，因为它是相当不同的答案，我已经放弃了。这怎么你可以开始创建自己的扫描仪类：

class Scanner : System.IO.StringReader
{
  string currentWord;

  public Scanner(string source) : base(source)
  {
     readNextWord();
  }

  private void ReadNextWord()
  {
     System.Text.StringBuilder sb = new StringBuilder();
     char nextChar;
     int next;
     do
     {
        next = this.Read();
        if (next < 0)
           break;
        nextChar = (char)next;
        if (char.IsWhiteSpace(nextChar))
           break;
        sb.Append(nextChar);
     } while (true);
     while((this.Peek() >= 0) && (char.IsWhiteSpace((char)this.Peek())))
        this.Read();
     if (sb.Length > 0)
        currentWord = sb.ToString();
     else
        currentWord = null;
  }

  public bool HasNextInt()
  {
     if (currentWord == null)
        return false;
     int dummy;
     return int.TryParse(currentWord, out dummy);
  }

  public int NextInt()
  {
     try
     {
        return int.Parse(currentWord);
     }
     finally
     {
        readNextWord();
     }
  }

  public bool HasNextDouble()
  {
     if (currentWord == null)
        return false;
     double dummy;
     return double.TryParse(currentWord, out dummy);
  }

  public double NextDouble()
  {
     try
     {
        return double.Parse(currentWord);
     }
     finally
     {
        readNextWord();
     }
  }

  public bool HasNext()
  {
     return currentWord != null;
  }
}

Answer 2

我相信这种扩展的方法 TextReader 会做的把戏：

public static class TextReaderTokenizer
{
    // Adjust as needed. -1 is EOF.
    private static int[] whitespace = { -1, ' ', '\r' , '\n', '\t' };

    public static T ReadToken<T>(this TextReader reader)
    {
        StringBuilder sb = new StringBuilder();
        while (Array.IndexOf(whitespace, reader.Peek()) < 0)
        {
            sb.Append((char)reader.Read());
        }
        return (T)Convert.ChangeType(sb.ToString(), typeof(T));
    }    
}

它可以用这样的：

TextReader reader = File.OpenText("foo.txt");
int n = reader.ReadToken<int>();
string s = reader.ReadToken<string>();

[编辑] 要求在问题的意见，这是一个实例包装版本的上面就是参数化与和符 CultureInfo:

public class TextTokenizer
{
    private TextReader reader;
    private Predicate<char> isDelim;
    private CultureInfo cultureInfo;

    public TextTokenizer(TextReader reader, Predicate<char> isDelim, CultureInfo cultureInfo)
    {
        this.reader = reader;
        this.isDelim = isDelim;
        this.cultureInfo = cultureInfo;
    }

    public TextTokenizer(TextReader reader, char[] delims, CultureInfo cultureInfo)
    {
        this.reader = reader;
        this.isDelim = c => Array.IndexOf(delims, c) >= 0;
        this.cultureInfo = cultureInfo;
    }

    public TextReader BaseReader
    {
        get { return reader; }
    }

    public T ReadToken<T>()
    {
        StringBuilder sb = new StringBuilder();
        while (true)
        {
            int c = reader.Peek();
            if (c < 0 || isDelim((char)c))
            {
                break;
            }
            sb.Append((char)reader.Read());
        }
        return (T)Convert.ChangeType(sb.ToString(), typeof(T));
    }    
}

样品的使用情况：

TextReader reader = File.OpenText("foo.txt");
TextTokenizer tokenizer = new TextTokenizer(
    reader,
    new[] { ' ', '\r', '\n', '\t' },
    CultureInfo.InvariantCulture);
int n = tokenizer.ReadToken<int>();
string s = tokenizer.ReadToken<string>();

Answer 3

你应该定义 到底 什么，你的文件的格式是为了看起来象。你会如何表示一串的空间吗？什么确定线路的终止去吗？

在一般可以使用 TextReader 及其 ReadLine 方法，随后通过 double.TryParse, int.TryParse 等等-但你需要销的格式下更多的第一次。

Answer 4

你有没有检查出BinaryReader类？是的，它是一个文本的文件，但没有什么阻止你把它作为二进制数据，因此使用BinaryReader.它拥有所有的方法，你正在寻找外ReadLine.但是这不会太难执行，方法上的BinaryReader.

Answer 5

如果你 做 需要的文本的文件(即UTF-8"或"ASCII码)之后的二进制位作家不会的工作。

你可以使用 TextReader, 但不同的是 BinaryReader 和 TextWriter 它不支持任何类型的其他线 char.你将必须定义什么是分离器都是允许的，并分析基线数据自己。

Answer 6

的 系统。IO.BinaryReader 类是你需要什么。

例的执行情况的一个 ReadLine 方法：

public static class Extensions
{
    public static String ReadLine(this BinaryReader binaryReader)
    {
        var bytes = new List<Byte>();
        byte temp;

        while ((temp = (byte)binaryReader.Read()) < 10)
            bytes.Add(temp);

        return Encoding.Default.GetString(bytes.ToArray());
    }
}

例如，对使用这类：

using System;
using System.IO;
using System.Security.Permissions;

class Test
{
    static void Main()
    {
        // Load application settings.
        AppSettings appSettings = new AppSettings();
        Console.WriteLine("App settings:\nAspect Ratio: {0}, " +
            "Lookup directory: {1},\nAuto save time: {2} minutes, " +
            "Show status bar: {3}\n",
            new Object[4]{appSettings.AspectRatio.ToString(),
            appSettings.LookupDir, appSettings.AutoSaveTime.ToString(),
            appSettings.ShowStatusBar.ToString()});

        // Change the settings.
        appSettings.AspectRatio   = 1.250F;
        appSettings.LookupDir     = @"C:\Temp";
        appSettings.AutoSaveTime  = 10;
        appSettings.ShowStatusBar = true;

        // Save the new settings.
        appSettings.Close();
    }
}

// Store and retrieve application settings.
class AppSettings
{
    const string fileName = "AppSettings#@@#.dat";
    float  aspectRatio;
    string lookupDir;
    int    autoSaveTime;
    bool   showStatusBar;

    public float AspectRatio
    {
        get{ return aspectRatio; }
        set{ aspectRatio = value; }
    }

    public string LookupDir
    {
        get{ return lookupDir; }
        set{ lookupDir = value; }
    }

    public int AutoSaveTime
    {
        get{ return autoSaveTime; }
        set{ autoSaveTime = value; }
    }

    public bool ShowStatusBar
    {
        get{ return showStatusBar; }
        set{ showStatusBar = value; }
    }

    public AppSettings()
    {
        // Create default application settings.
        aspectRatio   = 1.3333F;
        lookupDir     = @"C:\AppDirectory";
        autoSaveTime  = 30;
        showStatusBar = false;

        if(File.Exists(fileName))
        {
            BinaryReader binReader =
                new BinaryReader(File.Open(fileName, FileMode.Open));
            try
            {
                // If the file is not empty,
                // read the application settings.
                // First read 4 bytes into a buffer to
                // determine if the file is empty.
                byte[] testArray = new byte[3];
                int count = binReader.Read(testArray, 0, 3);

                if (count != 0)
                {
                    // Reset the position in the stream to zero.
                    binReader.BaseStream.Seek(0, SeekOrigin.Begin);

                    aspectRatio   = binReader.ReadSingle();
                    lookupDir     = binReader.ReadString();
                    autoSaveTime  = binReader.ReadInt32();
                    showStatusBar = binReader.ReadBoolean();
                }
            }

            // If the end of the stream is reached before reading
            // the four data values, ignore the error and use the
            // default settings for the remaining values.
            catch(EndOfStreamException e)
            {
                Console.WriteLine("{0} caught and ignored. " +
                    "Using default values.", e.GetType().Name);
            }
            finally
            {
                binReader.Close();
            }
        }

    }

    // Create a file and store the application settings.
    public void Close()
    {
        using(BinaryWriter binWriter =
            new BinaryWriter(File.Open(fileName, FileMode.Create)))
        {
            binWriter.Write(aspectRatio);
            binWriter.Write(lookupDir);
            binWriter.Write(autoSaveTime);
            binWriter.Write(showStatusBar);
        }
    }
}

Answer 7

你也许可以使用 系统。IO.文件 类阅读该文件， 系统。转换 分析串你从阅读该文件。

string line = String.Empty;
while( (line = file.ReadLine()).IsNullOrEmpty() == false )
{
   TYPE value = Convert.ToTYPE( line );
}

哪里 TYPE 是什么类型的你可以处理与在特定线路/文件。

如果有多种价值观的一线你可以做一个分割和读到的个人价值观如：

string[] parts = line.Split(' ');
if( parts.Length > 1 )
{
   foreach( string item in parts )
   {
      TYPE value = Convert.ToTYPE( item );
   }
}
else
{
   // Use the code from before
}