I want to do something like:
string s = "\\blabla";
when you write "\" it means there will only be a single '\'. How do I write the string so there will actually be 2 '\' meaning "\" ?
This works without a problem:
string s = "//blabla";
If you mean the backslash instead, you can use a verbatim string literal (using the # symbol to avoid processing escape symbols):
string s = #"\\blabla";
Alternatively you can escape the escape character itself:
string s = "\\\\blabla";
'/' is not the escape char, so you can simply write "//"
The escape char is '\' and, to use it properly, you can refer to the MSDN instructions.
Try this:
string s = #"\\blabla";
The '#' symbol treats whatever follows it as a verbatim string literal (ie: you won't need to worry about escape characters within the string).
I think you mean \ not /.
You could escape the \ with another backslash "\\\\" or you could use a string literal #"\\"
You may use # before strings to avoid having to escape special characters.
The advantage of #-quoting is that escape sequences are not processed,
which makes it easy to write
http://msdn.microsoft.com/en-us/library/362314fe(v=vs.71).aspx
Related
I would like to know what is a good way to escape back slashes in a string without adding unnecessary slashes to it.
I mean, usually if I want to escape a backslash in a string, the simplest way is to use String.Replace() like so:
string s = someString.Replace("\\", "\\\\");
A similar thing can be done with regular expressions using Regex.Replace().
Now my question is, lets say I have a string that has some of its back slashes escaped like for example: "C:\some_folder\\some_file.bin"
Now if I try and replace the backslashes in that by adding another backslash before each occurrence, I will end up with the following string:
"C:\\some_folder\\\\some_file.bin"
No clearly, the \\\\ are unnecessary, so how do I go about ignoring already escaped characters?
I think, this is what you want to do-
string path = #"C:\some_folder\\some_file.bin";
string exactPath = string.Join("\\",path.Split(new char[] { '\\' }, StringSplitOptions.RemoveEmptyEntries));
here is a RegEx Approach
string Result = Regex.Replace("C:\\some_folder\\\\some_file.bin", "[\\\\]+", "\\");
in that case you need to escape for RegEx AND for C#. alternatively you can write
string Result = Regex.Replace(#"C:\some_folder\\some_file.bin",#"[\\]+",#"\");
because "\\" equals #"\"
Maybe I am missing something here
I have a variable dir coming in looking something like \\\\SERVERNAME\\dir\\subdir
I need it to look like \\SERVERNAME\dir\subdir
I used string.Replace routine but it did not replace the double slashes, the problem is that when i try to use the path as is, it doesn't find the file.
How would I use string.Replace here in order to get a valid path?
dir.Replace(#"\\", #"\") should do the trick.
In C# the backslash character, "\", is used to escape characters in strings. For example, in the string "Hello\nworld", the "\n" represents a newline character. So, in general, when C# sees a "\" in a string it expects to treat it as part of a special command character, rather than as a literal "\".
So, how do you tell C# that you want a literal backslash to appear in your string, that it isn't part of a special command character? You escape the backslash. And the escape character is also a backslash. So to tell C# that you really want a literal "\" to appear in your string (eg in a file path) you use two backslashes: "\\".
Say I wanted to set a variable to the following path: C:\Temp\FileDrop
In C# I'd have to do the following:
string myPath = "C:\\Temp\\FileDrop";
I suspect that when you see the value of a variable looking like \\\\SERVERNAME\\dir\\subdir it is escaping the backslash characters so the real value of the variable is \\SERVERNAME\dir\subdir.
By the way, if you're copying and pasting long paths from, say, Windows Explorer, it can be a real pain to have to double up the backslashes to escape them. So C# has a special string literal character, "#". If you prefix a string with a "#" then it will treat the string exactly as written. eg
string myPath = #"C:\Temp\FileDrop";
Please forgive me a beginner's question :)
string S="abc";
S+="\";
won't complile.
string S="abc";
S+="\\";
will make S="abc\\"
How can I make S="abc\" ?
Your second piece of code is what you want (or a verbatim string literal #"\" as others have suggested), and it only adds a single backslash - print it to the console and you'll see that.
These two pieces of code:
S += "\\";
and
S += #"\";
are exactly equivalent. In both cases, a single backslash is appended1.
I suspect you're getting confused by the debugger view, which escapes backslashes (and some other characters). You can validate that even with the debugger by looking at S.Length, which you'll see is 4 rather than 5.
1 Note that it doesn't change the data in the existing string, but it sets the value of S to refer to a new string which consists of the original with a backslash on the end. String objects in .NET are immutable - but that's a whole other topic...
Try this:
String S = "abc";
S += #"\";
# = verbatim string literal
http://msdn.microsoft.com/en-us/library/aa691090%28v=vs.71%29.aspx
http://msdn.microsoft.com/en-us/library/vstudio/362314fe.aspx
string S = "abs" + "\\";
Should and does result in abc\.
What you are probably seeing is the way the debugger/intellisense visualizes the string for you.
Try printing your string to the console or display it in a textbox.
You already have the solution. The reason it appears as abc\\ whilst debugging is because VS will escape backslashes, print the value of S to a console window and you'll see abc\.
You could add an # to the start of the string literal, e.g.
string S="abc";
S+= #"\";
Which will achieve the same thing.
You can escape the backslash with the # character:
string S="abc";
S += #"\";
But this accomplishes exactly what you've written in your second example. The confusion on this is stemming from the fact that the Visual Studio debugger continues to escape these characters, even though your source string will contain only a single backslash.
Your second example is perfectly fine
string S="abc";
S+="\\";
Visual studio displays string escaped, that's why you see two slashes in result string. If you don't want to use escaping declare string like this
#"\"
This is not compiling because compiler is expecting a character after escape symbol
string S="abc";
S+="\";
string S="abc";
S+="\\";
Console.WriteLine(S); // This is what you're missing ;)
You'll see your string is not wrong at all.
The backslash (\) is an escape character, and allows you to get special characters that you wouldn't normally be able to insert in a string, such as "\r\n", which represents a NewLine character, or "\"" which basically gives you a " character.
In order to get the \ character, you need to input "\\" which is exactly what you're doing and also what you want.
Using the verbatim (#) replaces all occurrences of \ into \\, so #"\" == "\\". This is usually used for paths and regexes, where literal \ are needed in great numbers. Saying #"C:\MyDirectory\MyFile" is more comfortable than "C:\\MyDirectory\\MyFile" after all.
Try this
string s="abc";
s = s+"\\";
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Closed 10 years ago.
Possible Duplicate:
What's the # in front of a string in C#?
why do we use # to replace \ with another string using string.replace(#"\","$$")
i'm using C# windows application
The # in front of a string literal makes it a verbatim string literal, so the backslash \ does not need to be doubled. You can use "\\" instead of #"\" for the same effect.
Because if you didn't, you'd have to escape \ with \\
# is used to what's called verbatim strings
In C#, you can prefix a string with # to make it verbatim, so you don't need to escape special characters.
#"\"
is identical to
"\\"
The C# Language Specification 2.4.4.5 String literals states:
C# supports two forms of string literals: regular string literals and
verbatim string literals.
A regular string literal consists of zero or more characters enclosed
in double quotes, as in "hello", and may include both simple escape
sequences (such as \t for the tab character), and hexadecimal and
Unicode escape sequences.
A verbatim string literal consists of an # character followed by a
double-quote character, zero or more characters, and a closing
double-quote character. A simple example is #"hello". In a verbatim
string literal, the characters between the delimiters are interpreted
verbatim, the only exception being a quote-escape-sequence. In
particular, simple escape sequences, and hexadecimal and Unicode
escape sequences are not processed in verbatim string literals. A
verbatim string literal may span multiple lines.
The verbatim string literal, which uses the # character, makes it a little easier in practicality to escape almost all the characters that you would otherwise have to escape individually with the \ character in a string.
Note: the " char will still require escaping even with the verbatim mode.
So I would use it to save time from having to go through a long string to escape all the necessary characters that needed escaping.
Because the backslash is treated as an escape character and you would get an 'Unrecognised escape sequence' error if you didn't use '#'. Using '#' tells the compiler to ignore escape characters. this may be helpful.
Am using regex.Replace() to replace the whole occurrence of a string.. so I gave like Regex.Replace(str,#stringToReplace,"**"); where stringToReplace = #"session" + "\b";
if i give like that its not replacing.. but if i give like Regex.Replace(str,#"session\b","**"); then its working.. how to avoid this.. i want to pass value which will be set dynamically..
Thanks
nimmi
try
stringToReplace = #"session" + #"\b";
The # here means a verbatim string literal.
When you write "\b" without the # it means the backspace character, i.e. the character with ASCII code 8. You want the string consisting of a backslash followed by a b, which means a word boundary when in a regular expression.
To get this you need to either escape the backslash to make it a literal backslash: "\\b" or make the second string also into a verbatim string literal: #"\b". Note also that the # in #"session" (without the \b) doesn't actually have an effect, although there is no harm in leaving it there.
stringToReplace = "session" + #"\b";
#"session" + "\b"
and
#"session\b"
are not the same string.
In the first case "\b" you don't treat the slash as a slash but as an escape parameter. In the second case you do.
So #"session" + #"\b" should bring the same result