I have a string that is returned to me which contains escape characters.
Here is a sample string
"test\40gmail.com"
As you can see it contains escape characters. I need it to be converted to its real value which is
How can I do this?
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3Is this the only case, or are there many different control characters that you'll have to account for?Jason Down– Jason Down2012-07-20 17:27:37 +00:00Commented Jul 20, 2012 at 17:27
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Both HttpUtility and WebUtility have decoding methods - please reference this stackoverflow.com/questions/122641/…Mike Perrenoud– Mike Perrenoud2012-07-20 17:30:07 +00:00Commented Jul 20, 2012 at 17:30
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1Are you working in a web environment? (i.e. do you already have a reference to System.Web in your project). Or do you need something that is independent?James– James2012-07-20 17:31:17 +00:00Commented Jul 20, 2012 at 17:31
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5 Answers
If you are looking to replace all escaped character codes, not only the code for @, you can use this snippet of code to do the conversion:
public static string UnescapeCodes(string src) {
var rx = new Regex("\\\\([0-9A-Fa-f]+)");
var res = new StringBuilder();
var pos = 0;
foreach (Match m in rx.Matches(src)) {
res.Append(src.Substring(pos, m.Index - pos));
pos = m.Index + m.Length;
res.Append((char)Convert.ToInt32(m.Groups[1].ToString(), 16));
}
res.Append(src.Substring(pos));
return res.ToString();
}
The code relies on a regular expression to find all sequences of hex digits, converting them to int, and casting the resultant value to a char.
Gianluca Ghettini
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answered Jul 20, 2012 at 17:44
Sergey Kalinichenko
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4 Comments
James
I'm a little confused with regex and C# (so many escape characters). Could you possibly post the regex string by itself (not formatted for C# use)?
Sergey Kalinichenko
@James Sure, it's
\\([0-9A-Fa-f]+) (here, the slash is escaped for the regex engine, but not for the compiler).
Dominic Cronin
It's handy when working with regexes to use a C# "verbatim string literal".. e.g.
var rx = new Regex(@"\\([0-9A-Fa-f]+)");Gianluca Ghettini
res.Append(src.Substring(pos, m.Index)); should be res.Append(src.Substring(pos, m.Index - pos));
.NET provides the static methods Regex.Unescape and Regex.Escape to perform this task and back again. Regex.Unescape will do what you need.
https://learn.microsoft.com/en-us/dotnet/api/system.text.regularexpressions.regex.unescape
Comments
string test = "test\40gmail.com";
test.replace(@"\40","@");
If you want a more general approach ...
5 Comments
Micah Armantrout
please explain how it would not
MethodMan
he probably saw your previous answer prior to the edit.. your answer will work Micah
crashmstr
When I first saw it, it had
test.replace("\40","");, and @dasblinkenlight's commment would be true.
Tim S.
You need
@"\40" (same with test's declaration) so that C# takes it verbatim.
Ryan Kohn
I downvoted this because the answer applies only to the sample string, and not to the general case.
The sample string provided ("test\40gmail.com") is JID escaped. It is not malformed, and HttpUtility/WebUtility will not correctly handle this escaping scheme.
You can certainly do it with string or regex functions, as suggested in the answers from dasblinkenlight and C.Barlow. This is probably the cleanest way to achieve the desired result. I'm not aware of any .NET libraries for decoding JID escaping, and a brief search hasn't turned up much. Here is a link to some source which may be useful, though.
answered Jul 20, 2012 at 18:07
Esoteric Screen Name
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3 Comments
Micah Armantrout
You are assuming that he is using Jabber / chat client when this is not stated
Esoteric Screen Name
@MicahArmantrout No, I'm not. I didn't say he was using that client, I said he has strings escaped in the same fashion. Using
\(hex value) to indicate an escaped character is not platform dependent.Esoteric Screen Name
@MicahArmantrout No. I am absolutely not making that assumption.
I just wrote this piece of code and it seems to work beautifully... It requires that the escape sequence is in HEX, and is valid for value's 0x00 to 0xFF.
// Example
str = remEscChars(@"Test\x0D") // str = "Test\r"
Here is the code.
private string remEscChars(string str)
{
int pos = 0;
string subStr = null;
string escStr = null;
try
{
while ((pos = str.IndexOf(@"\x")) >= 0)
{
subStr = str.Substring(pos + 2, 2);
escStr = Convert.ToString(Convert.ToChar(Convert.ToInt32(subStr, 16)));
str = str.Replace(@"\x" + subStr, escStr);
}
}
catch (Exception ex)
{
throw ex;
}
return str;
}
