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.
Related
I have a parameter passed through my url which is as followed:
eu\test5.
When I print this string it says eu est5, it is replacing the \t.
How can I make sure my string is not exaping anything?
I want to grab all the data after the backslash, so I have the value test5.
string user = "eu\test5";
int backslashPos = user.IndexOf("\\");
label2.Text = user.Substring(backslashPos);
Add an # in front of the string or use "\\".
string user = #"eu\test5";
string user = "eu\\test5";
\ is used for escape sequences, which is used for several commands inside a string. Like \n for a New Line
Using an # ignores all escape sequences in a string.
Here is a list of all escape sequences link
\t is an escape sequence representing a set of spaces. So the result you are getting is obvious.
I am really confused here. I have written a snippet of code in C# that is passed a possible file pathway. If it contains a character specified in a regex string, it should return false. However, the regex function Match refuses to find anything matching (I even set it to a singular character I knew was in the string), resulting in severe irritation from me.
The code is:
static bool letterTest(string pathway)
{
bool validPath = false;
char[] c = Path.GetInvalidPathChars();
string test = new string(c);
string regex = "["+test+"]";
string spTest = "^[~#%&*\\{}+<>/\"|]";
Match match = Regex.Match(pathway, spTest);
if (!match.Success)
{
validPath = true;
}
return validPath;
}
The string I pass to it is: #"C:/testing/invalid#symbol"
What am I doing wrong/misunderstanding with the regex, or is it something other than the regex that I have messed up?
Remove the initial caret from your regex:
[~#%&*\\{}+<>/\"|]
You are requiring that the path begin with one of those characters. By removing that constraint, it will search the whole string for any of those characters.
But why not use the framework to do the work for you?
Check this out: Check if a string is a valid Windows directory (folder) path
Instead of a regular expression you can just do the following.
static bool letterTest(string pathway)
{
char[] badChars = Path.GetInvalidPathChars();
return pathway.All(c => !badChars.Contains(c));
// or
// return !pathway.Any(c => badChars.Contains(c));
// or
// return badChars.All(bc => !pathway.Contains(bc));
// or
// return !badChars.Any(bc => pathway.Contains(bc));
}
Someone has already pointed out the caret that was anchoring your match to the first character. But there's another error you may not be aware of yet. This one has to do with your use of string literals. What you have now is a traditional, C-style string literal:
"[~#%&*\\{}+<>/\"|]"
...which becomes this regex:
[~#%&*\{}+<>/"|]
The double backslash has become a single backslash, which is treated as an escape for the following brace (\{). The brace doesn't need escaping inside a character class, but it's not considered a syntax error.
However, the regex will not detect a backslash as you intended. To do that, you need two backslashes in the regex, so there should be four backslashes in the string literal:
"[~#%&*\\\\{}+<>/\"|]"
Alternatively, you can use a C# verbatim string literal. Backslashes have no special meaning in a verbatim string. The only thing that needs special handling is the quotation mark, which you escape by adding another quotation mark:
#"[~#%&*\\{}+<>/""|]"
you have to escape the / literal
"^[~#%&*\\{}+<>\/\"|]"
Caret stands for negation of the character group. Removing it from spTest solves this issue.
string spTest = "[~#%&*\\{}+<>/\"|]";
Here is my function, I'm trying to replace a string in a file, but c# tells me my regex is malformed. Any ideas?
public void function(string fileName, string path) {
string pathToAmmend = #"$SERVERROOT\pathpath";
string newPath = #"$SERVERROOT\" + path;
File.WriteAllText(fileName, Regex.Replace(File.ReadAllText(fileName), pathToAmmend, newPath));
....
}
It works if i change the strings to:
string pathToAmmend = #"$SERVERROOT\\pathpath";
string newPath = #"$SERVERROOT\\" + path;
But then I have two slashes and I only want one slash.
It sounds like you don't actually need a regular expression at all. It sounds like you quite possibly just want string.Replace:
// Split into three statements for clarity.
string input = File.ReadAllText(fileName);
string output = input.Replace(pathToAmend, newPath);
File.WriteAllText(output);
Only use regular expressions when you're genuinely trying to match patterns.
A \ is a special escaping character in regular expressions. You have to escape it so that it will be interpreted as a literal \ and not an escape sequence. $ is also a special character (an end anchor), so you'll want to escape that as well.
string pathToAmmend = #"\$SERVERROOT\\pathpath";
Using # to create a verbatim string only means you don't have to escape the \ for the sake of the C# compiler. You still have escape the \ for in a regular expression pattern. Without the verbatim string this would be:
string pathToAmmend = "\\$SERVERROOT\\\\pathpath";
Of course, as Jon Skeet points out, for something this simple, regular expressions aren't really the best way to go here.
I have a String with a path in it.
It looks like this :
TaskManager = "RegistryKey objRegistryKey = Registry.CurrentUser.CreateSubKey("Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System");"
I want to use this string to compile with codedom, but I get an error saying "cant find Software\Microsoft......".
Is there anyway to replace the " with another char?
I use verbatim string literal for paths so I don't have to double the backslashes:
TaskManager = #"RegistryKey objRegistryKey = Registry.CurrentUser.CreateSubKey(""Software\Microsoft\Windows\CurrentVersion\Policies\System"");"
" is doubled ""
to write " inside a string use \"
String str= "my string with \"quotes\""; // my string with "quotes"
the character \ is used to write special character inside a string for example a \t write inside the string a tab and \n make the string go to a new line
or
String str= #"my string with ""quotes"""; //same as before
the character # before a string make the compiler take the string as is, every special character is written without having to use \ before it, the only character that need to be escaped are the quotes itself that you write by doubling them ""
Watch out that iff you use the method with # your \ \ in the path become \
If you are trying to escape the qoute then do something like this:
TaskManager = "RegistryKey objRegistryKey = Registry.CurrentUser.CreateSubKey(\"Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\");"
Use \"
to get a double quote, the same way as you used \ to get a backslash.
TaskManager = "RegistryKey objRegistryKey = Registry.CurrentUser.CreateSubKey(\"Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\");"
That should fix it.
you can use it this way
TaskManager = "RegistryKey objRegistryKey = Registry.CurrentUser.CreateSubKey('Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System');"
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.