c# How to escape a directory path with differend letters? - c#

Hi there I have this
string s = #"A:\"
And i have to change the letter, so i need this
string s= #" + Letter + :\"
I already tried something, but it was lame...

Try this:
string s = Letter + #":\";
If you're using C# 6.0, you could use interpolated strings. (but you need to escape the \)
string s = $"{Letter}:\\";

You either need to escape the backslash, because it's a special character, by using two backslashes, like this:
string s = Letter + ":\\"
or you need to indicate that the string with the backslash should be interpreted "verbatim" by putting an # in front of it, like this:
string s = Letter + #":\"

You can use string format to help. There is also string interpolation if you are using c# 6.0.
var Letter = "A";
string s = string.Format(#"{0}:\", Letter);
String interpolation with c# 6.0
string s = $"{Letter}:\\";

Related

String pattern delimiter

I have this code:
string first = "2-18;1-4; 5-212; 4-99" ;
Char delimiter = '-';
String pattern = #"\s?(\d+)([-])(\d+)";
And I would like to know if there is any way to put the delimiter in the pattern instead of the ([-]) ?
You could use string interpolation:
string first = "2-18;1-4; 5-212; 4-99" ;
Char delimiter = '-';
String pattern = $#"\s?(\d+)([{delimiter}])(\d+)";
The $ sign (which has to be in front of the #) makes it possible to put a variable (string) in a string by using { }
Note: In older versions of C# however this will not work
In this case you can use string.Format:
string.Format(#"\s?(\d+)([{0}])(\d+)", delimiter);
This works the same way but uses number placeholders for the parameters after the ,
Regex.Escape: (Credits to NtFreX)
Additionally if you are using regex you should escape your character (because they can mean something else in regex).
$#"\s?(\d+)([{Regex.Escape( delimiter.ToString() )}])(\d+)";
This is simplest string concatenation. You have several options:
string concatenation:
Char delimiter = '-';
String pattern = #"\s?(\d+)([" + delimiter + "])(\d+)";
string.Format():
Char delimiter = '-';
String pattern = string.Format(#"\s?(\d+)([{0}])(\d+)", delimiter);
new style Format (only works with newer C# versions):
Char delimiter = '-';
String pattern = $#"\s?(\d+)([{delimiter}])(\d+)";
Additionaly I would use Regex.Escape to escape the delimiter.
$#"\s?(\d+)([{Regex.Escape(delimiter)}])(\d+)";
For example if the delimiter is . it needs to be changed into \. because . is a special regex character which matches any character. The same goas for other characters.

Regex replace special characters defind by client

I need a c# function which will replace all special characters customized by the client from a string Example
string value1 = #"‹¥ó׬¶ÝÆ";
string input1 = #"Thi¥s is\123a strÆing";
string output1 = Regex.Replace(input1, value1, "");
I want have a result like this : output1 =Thi s is\123a str ing
Why do you need regex? This is more efficient, concise also readable:
string result = string.Concat(input1.Except(value1));
If you don't want to remove but replace them with a different string you can still use a similar(but not as efficient) approach:
string replacement = "[foo]";
var newChars = input1.SelectMany(c => value1.Contains(c) ? replacement : c.ToString());
string result = string.Concat( newChars ); // Thi[foo]s is\123a str[foo]ing
Someone asked for a regex?
string value1 = #"^\-[]‹¥ó׬¶ÝÆ";
string input1 = #"T-^\hi¥s is\123a strÆing";
// Handles ]^-\ by escaping them
string value1b = Regex.Replace(value1, #"([\]\^\-\\])", #"\$1");
// Creates a [...] regex and uses it
string input1b = Regex.Replace(input1, "[" + value1b + "]", " ");
The basic idea is to use a [...] regex. But first you have to escape some characters that have special meaning inside a [...]. They should be ]^-\ Note that you don't need to escape the [
note that this solution isn't compatible with non-BMP unicode characters (characters that fill-up two char)
A solution that is compatible with them is more complex, but for normal use it shouldn't be a problem.

How to concatenate string with a backslash with another string

How can I concatenate the string "\u" with "a string" to get "\u0000"?
My code creates two backslashes:
string a = #"\u" + "0000"; //ends up being "\\\u0000";
The escape sequence \uXXXX is part of the language's syntax and represents a single Unicode character. By contrast, #"\u" and "0000" are two different strings, with a total of six characters. Concatenating them won't magically turn them into a single Unicode escape.
If you're trying to convert a Unicode code point into a single-character string, do this:
char.ConvertFromUtf32(strUnicodeOfMiddleChar).ToString()
BTW, don't use == true; it's redundant.
If I understand you correctly, I think you want to build a single-char string from an arbitrary Unicode value (4 hex digits). So given the string "0000", you want to convert that into the string "\u0000", i.e., a string containing a single character.
I think this is what you want:
string f = "0000"; // Or whatever
int n = int.Parse(f, NumberStyles.AllowHexSpecifier);
string s = ((char) n).ToString();
The resulting string s is "\u0000", which you can then use for your search.
(With corrections suggested by Thomas Levesque.)
the line below creates tow backslash:
string a = #"\u" + "0000"; //a ends up being "\\u0000";
No, it doesn't; the debugger shows "\" as "\", because that's how you write a backslash in C# (when you don't prefix the string with #). If you print that string, you will see \u0000, not \\u0000.
Nope, that string really has single backslash in. Print it out to the console and you'll see that.
Escape your characters correctly!!
Both:
// I am an escaped '\'.
string a = "\\u" + "0000";
And:
// I am a literal string.
string a = #"\u" + "0000";
Will work just fine. But, and I am going out on a limb here, I am guessing that you are trying to escape a Unicode Character and Hex value so, to do that, you need:
// I am an escaped Unicode Sequence with a Hex value.
char a = '\uxxxx';

Replacing double backwards slashes with single ones in c#

I need to replace double quotes with single so that something like this
\\\\servername\\dir1\\subdir1\\
becomes
\\servername\dir1\subdir1\
I tried this
string dir = "\\\\servername\\dir1\\subdir1\\";
string s = dir.Replace(#"\\", #"\");
The result I get is
\\servername\\dir1\\subdir1\\
Any ideas?
You don't need to replace anything here. The backslashes are escaped, that's why they are doubled.
Just like \t represents a tabulator, \\ represents a single \. You can see the full list of Escape Sequences on MSDN.
string dir = "\\\\servername\\dir1\\subdir1\\";
Console.WriteLine(dir);
This will output \\servername\dir1\subdir1\.
BTW: You can use the verbatim string to make it more readable:
string dir = #"\\servername\dir1\subdir1\";
There is no problem with the code for replacing. The result that you get is:
\servername\dir1\subdir1\
When you are looking at the result in the debugger, it's shown as it would be written as a literal string, so a backslash characters is shown as two backslash characters.
The string that you create isn't what you think it is. This code:
string dir = "\\\\servername\\dir1\\subdir1\\";
produces a string containing:
\\servername\dir1\subdir1\
The replacement code does replace the \\ at the beginning of the string.
If you want to produce the string \\\\servername\\dir1\\subdir1\\, you use:
string dir = #"\\\\servername\\dir1\\subdir1\\";
or:
string dir = "\\\\\\\\servername\\\\dir1\\\\subdir1\\\\";
This string "\\\\servername\\dir1\\subdir1\\" is the same as #"\\servername\dir1\subdir1\". In order to escape backslashes you need either use # symbol before string, or use double backslash instead of one.
Why you need that? Because in C# backslash used for escape sequences.

How to quote \" (slash double-quote) in a string literal?

This is probably a really simple question but I can't seem to get my head around it. I need to have a string that contains \" without it seeing it as an escape character. I tried using # but it won't work. The only other way I thought of doing this would be to use \u0022 but don't want to unless I can help it.
Desired string - string s = "\"\""; // Obviously this doesn't work!
Desired console output - \"\"
Hope this makes sense.
Thanks!
Try
string s = "\\\"\\\"";
You have to escape your backslashes too.
Mike
You can use the literal, but you need to double-up quotes.
string s = #"\""\""";
In verbatim string literals (#"...") a " in the string value is encoded as "", which happens to also be the only escape sequence in verbatim strings.
#"\""Happy coding!\""" // => \"Happy coding!\"
"\\\"Happy coding!\\\"" // => \"Happy coding!\"
Note that in the 2nd case (not a verbatim string literal), a \ is required before the \ and the " to escape them and prevent their normal meanings.
See the C# string reference for more details and examples.
I think you have to escape backslashes too... so something like "\\\"\\\"" should work, I believe.
Use this string:
string s = "\\\"\\\"";
Console.WriteLine( "\\\"\\\"" );
Just put a \ before each character that needs to be printed.
String s = #"\""\""";
DblQuote characters will escape a second dblquote character
Though for better readability I would go with:
const String DOUBLEQUOTE = """";
const String BACKSLASH = #"\";
String s = BACKSLASH + DOUBLEQUITE + BACKSLASH + DOUBLEQUOTE;
In a verbatim string (a string starting with #"") to escape double quotes you use double quotes, e.g. #"Please press ""Ok"".". If you want to do it with verbatim strings then you would do something like #"\""" (that's 3 double quotes on the end there).
You can do like this,
string s = "something'\\\'";
Use a single '' rather then "" in string to do the same.

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