将Unicode字符串转换为转义的ASCII字符串

Question

我该如何转换这个字符串:

This string contains the Unicode character Pi(?)

转换为转义的ASCII字符串:

This string contains the Unicode character Pi(\u03a0)

和反之亦然？

C#中可用的当前编码将π字符转换为"？".我需要保留那个角色.

Answer 1

这往返于\ uXXXX格式.

class Program {
    static void Main( string[] args ) {
        string unicodeString = "This function contains a unicode character pi (\u03a0)";

        Console.WriteLine( unicodeString );

        string encoded = EncodeNonAsciiCharacters(unicodeString);
        Console.WriteLine( encoded );

        string decoded = DecodeEncodedNonAsciiCharacters( encoded );
        Console.WriteLine( decoded );
    }

    static string EncodeNonAsciiCharacters( string value ) {
        StringBuilder sb = new StringBuilder();
        foreach( char c in value ) {
            if( c > 127 ) {
                // This character is too big for ASCII
                string encodedValue = "\\u" + ((int) c).ToString( "x4" );
                sb.Append( encodedValue );
            }
            else {
                sb.Append( c );
            }
        }
        return sb.ToString();
    }

    static string DecodeEncodedNonAsciiCharacters( string value ) {
        return Regex.Replace(
            value,
            @"\\u(?<Value>[a-zA-Z0-9]{4})",
            m => {
                return ((char) int.Parse( m.Groups["Value"].Value, NumberStyles.HexNumber )).ToString();
            } );
    }
}

输出:

该函数包含一个unicode字符pi(π)

此函数包含一个unicode字符pi(\ u03a0)

该函数包含一个unicode字符pi(π)

Answer 2

对于Unescape您可以简单地使用此功能:

System.Text.RegularExpressions.Regex.Unescape(string)

System.Uri.UnescapeDataString(string)

我建议使用这种方法(它适用于UTF-8):

UnescapeDataString(string)

Answer 3

string StringFold(string input, Func<char, string> proc)
{
  return string.Concat(input.Select(proc).ToArray());
}

string FoldProc(char input)
{
  if (input >= 128)
  {
    return string.Format(@"\u{0:x4}", (int)input);
  }
  return input.ToString();
}

string EscapeToAscii(string input)
{
  return StringFold(input, FoldProc);
}