在c#中,我可以将字符串值转换为字符串文字,我将在代码中看到它的方式吗?我想用转义序列替换制表符,换行符等。
如果这段代码:
Console.WriteLine(someString);
生产:
Hello
World!
我想要这样的代码:
Console.WriteLine(ToLiteral(someString));
生产:
\tHello\r\n\tWorld!\r\n
在c#中,我可以将字符串值转换为字符串文字,我将在代码中看到它的方式吗?我想用转义序列替换制表符,换行符等。
如果这段代码:
Console.WriteLine(someString);
生产:
Hello
World!
我想要这样的代码:
Console.WriteLine(ToLiteral(someString));
生产:
\tHello\r\n\tWorld!\r\n
当前回答
public static class StringEscape
{
static char[] toEscape = "\0\x1\x2\x3\x4\x5\x6\a\b\t\n\v\f\r\xe\xf\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f\"\\".ToCharArray();
static string[] literals = @"\0,\x0001,\x0002,\x0003,\x0004,\x0005,\x0006,\a,\b,\t,\n,\v,\f,\r,\x000e,\x000f,\x0010,\x0011,\x0012,\x0013,\x0014,\x0015,\x0016,\x0017,\x0018,\x0019,\x001a,\x001b,\x001c,\x001d,\x001e,\x001f".Split(new char[] { ',' });
public static string Escape(this string input)
{
int i = input.IndexOfAny(toEscape);
if (i < 0) return input;
var sb = new System.Text.StringBuilder(input.Length + 5);
int j = 0;
do
{
sb.Append(input, j, i - j);
var c = input[i];
if (c < 0x20) sb.Append(literals[c]); else sb.Append(@"\").Append(c);
} while ((i = input.IndexOfAny(toEscape, j = ++i)) > 0);
return sb.Append(input, j, input.Length - j).ToString();
}
}
其他回答
有趣的问题。
如果你找不到更好的方法,你可以随时替换。 如果你选择它,你可以使用这个c#转义序列列表:
\' - single quote, needed for character literals \" - double quote, needed for string literals \ - backslash \0 - Unicode character 0 \a - Alert (character 7) \b - Backspace (character 8) \f - Form feed (character 12) \n - New line (character 10) \r - Carriage return (character 13) \t - Horizontal tab (character 9) \v - Vertical quote (character 11) \uxxxx - Unicode escape sequence for character with hex value xxxx \xn[n][n][n] - Unicode escape sequence for character with hex value nnnn (variable length version of \uxxxx) \Uxxxxxxxx - Unicode escape sequence for character with hex value xxxxxxxx (for generating surrogates)
这个列表可以在c#常见问题中找到 有哪些字符转义序列可用?
我提交了自己的实现,它处理空值,并且由于使用数组查找表、手动十六进制转换和避免开关语句,因此性能应该更好。
using System;
using System.Text;
using System.Linq;
public static class StringLiteralEncoding {
private static readonly char[] HEX_DIGIT_LOWER = "0123456789abcdef".ToCharArray();
private static readonly char[] LITERALENCODE_ESCAPE_CHARS;
static StringLiteralEncoding() {
// Per http://msdn.microsoft.com/en-us/library/h21280bw.aspx
var escapes = new string[] { "\aa", "\bb", "\ff", "\nn", "\rr", "\tt", "\vv", "\"\"", "\\\\", "??", "\00" };
LITERALENCODE_ESCAPE_CHARS = new char[escapes.Max(e => e[0]) + 1];
foreach(var escape in escapes)
LITERALENCODE_ESCAPE_CHARS[escape[0]] = escape[1];
}
/// <summary>
/// Convert the string to the equivalent C# string literal, enclosing the string in double quotes and inserting
/// escape sequences as necessary.
/// </summary>
/// <param name="s">The string to be converted to a C# string literal.</param>
/// <returns><paramref name="s"/> represented as a C# string literal.</returns>
public static string Encode(string s) {
if(null == s) return "null";
var sb = new StringBuilder(s.Length + 2).Append('"');
for(var rp = 0; rp < s.Length; rp++) {
var c = s[rp];
if(c < LITERALENCODE_ESCAPE_CHARS.Length && '\0' != LITERALENCODE_ESCAPE_CHARS[c])
sb.Append('\\').Append(LITERALENCODE_ESCAPE_CHARS[c]);
else if('~' >= c && c >= ' ')
sb.Append(c);
else
sb.Append(@"\x")
.Append(HEX_DIGIT_LOWER[c >> 12 & 0x0F])
.Append(HEX_DIGIT_LOWER[c >> 8 & 0x0F])
.Append(HEX_DIGIT_LOWER[c >> 4 & 0x0F])
.Append(HEX_DIGIT_LOWER[c & 0x0F]);
}
return sb.Append('"').ToString();
}
}
我试图将ToVerbatim添加到Hallgrim公认的答案中:
private static string ToLiteral(string input)
{
using (var writer = new StringWriter())
{
using (var provider = CodeDomProvider.CreateProvider("CSharp"))
{
provider.GenerateCodeFromExpression(new CodePrimitiveExpression(input), writer, new CodeGeneratorOptions { IndentString = "\t" });
var literal = writer.ToString();
literal = literal.Replace(string.Format("\" +{0}\t\"", Environment.NewLine), "");
return literal;
}
}
}
private static string ToVerbatim(string input)
{
string literal = ToLiteral(input);
string verbatim = "@" + literal.Replace(@"\r\n", Environment.NewLine);
return verbatim;
}
使用Regex.Escape(字符串):
正则表达式。Escape转义最小字符集(,*,+,?,|,{,[, (,), ^, $,。, #和空白),用转义符替换它们 代码。
一个更结构化的方法,包括字符串和字符的所有转义序列,是:
它不会用对应的文字替换Unicode字符。它也不能煮鸡蛋。
public class ReplaceString
{
static readonly IDictionary<string, string> m_replaceDict
= new Dictionary<string, string>();
const string ms_regexEscapes = @"[\a\b\f\n\r\t\v\\""]";
public static string StringLiteral(string i_string)
{
return Regex.Replace(i_string, ms_regexEscapes, match);
}
public static string CharLiteral(char c)
{
return c == '\'' ? @"'\''" : string.Format("'{0}'", c);
}
private static string match(Match m)
{
string match = m.ToString();
if (m_replaceDict.ContainsKey(match))
{
return m_replaceDict[match];
}
throw new NotSupportedException();
}
static ReplaceString()
{
m_replaceDict.Add("\a", @"\a");
m_replaceDict.Add("\b", @"\b");
m_replaceDict.Add("\f", @"\f");
m_replaceDict.Add("\n", @"\n");
m_replaceDict.Add("\r", @"\r");
m_replaceDict.Add("\t", @"\t");
m_replaceDict.Add("\v", @"\v");
m_replaceDict.Add("\\", @"\\");
m_replaceDict.Add("\0", @"\0");
//The SO parser gets fooled by the verbatim version
//of the string to replace - @"\"""
//so use the 'regular' version
m_replaceDict.Add("\"", "\\\"");
}
static void Main(string[] args){
string s = "here's a \"\n\tstring\" to test";
Console.WriteLine(ReplaceString.StringLiteral(s));
Console.WriteLine(ReplaceString.CharLiteral('c'));
Console.WriteLine(ReplaceString.CharLiteral('\''));
}
}