string testStr="thestringhasa\slash";
if(testStr.Contains("\"))
{
//Code to process string with \
}
How do I properly test to see if a string contains a backslash, when I try the it statement if says a New Line in constant.
The other two answers are entirely correct, but no one bothered to explain why. The \ character has a special purpose in C# strings. It is the escape character, so to have a string that contains a slash, you have to use one of two methods.
Use the string literal symbol #. A string preceded by the # symbol tells the C# compiler to treat the string as a literal and not escape anything.
Use the escape character to tell the C# compiler there is a special character that is actually part of the string.
So, the following strings are equivalent:
var temp1 = #"test\test";
var test2 = "test\\test";
test1 == test2; // Yields true
You should use double slashes
string testStr=#"thestringhasa\slash";
if(testStr.Contains("\\"))
{
//Code to process string with \
}
The backslash must be escaped. Try the following:
string testStr = #"thestringhasa\slash";
if (testStr.Contains("\\"))
{
//Code to process string with \
}
Related
string s = "P\04";
string z = s.Replace('\\', '-');
Console.WriteLine(z);
I need to replace '\' character in to '-' character in a string. I tried several ways to replace, couldn't able to do for '\' character only.
Please any one suggest a way to do this
Your code to replace the \ is fine. The problem is with your input string, where the \ escapes the 0. It would work if you had this:
string s = "P\\04";
string z = s.Replace('\\', '-');
Console.WriteLine(z);
The output is P-04 assuming that's what you expect.
string s = #"P\04";
string z = s.Replace('\\', '-');
Console.WriteLine(z);
Add # at the before value of string s to make it a verbatim. That way '\' is treated as is. Otherwise \0 are treated as one character to make a different character.
You can also use Regex,
var result = Regex.Replace(#"P\04", #"\\", #"-");
Console.WriteLine(result);
FIDDLE
I have a long string (a path) with double backslashes, and I want to replace it with single backslashes:
string a = "a\\b\\c\\d";
string b = a.Replace(#"\\", #"\");
This code does nothing...
b remains "a\\b\\c\\d"
I also tried different combinations of backslashes instead of using #, but no luck.
Because you declared a without using #, the string a does not contain any double-slashes in your example. In fact, in your example, a == "a\b\c\d", so Replace does not find anything to replace. Try:
string a = #"a\\b\\c\\d";
string b = a.Replace(#"\\", #"\");
In C#, you can't have a string like "a\b\c\d", because the \ has a special meaning: it creates a escape sequence together with a following letter (or combination of digits).
\b represents actually a backspace, and \c and \d are invalid escape sequences (the compiler will complain about an "Unrecognized escape sequence").
So how do you create a string with a simple \? You have to use a backslash to espace the backslash:\\ (it's the espace sequence that represents a single backslash).
That means that the string "a\\b\\c\\d" actually represents a\b\c\d (it doesn't represent a\\b\\c\\d, so no double backslashes). You'll see it yourself if you try to print this string.
C# also has a feature called verbatim string literals (strings that start with #), which allows you to write #"a\b\c\d" instead of "a\\b\\c\\d".
You're wrong. "\\" return \ (know as escaping)
string a = "a\\b\\c\\d";
System.Console.WriteLine(a); // prints a\b\c\d
string b = a.Replace(#"\\", #"\");
System.Console.WriteLine(b); // prints a\b\c\d
You don't even need string b = a.Replace(#"\\", #"\");
this works
You don't even need string b = a.Replace(#"\", #"\");
but like if we generate a dos command through c# code... eg:- to delete a file
this wil help
I did this in a code in a UWP application.
foreach (var item in Attendances)
{
string a = item.ImagePath;
string b = a.Replace(#"\\", "/");
string c = a.Replace("\\", "/");
Console.WriteLine(b);
Console.WriteLine(a);
item.ImagePath = c;
}
and the ones without the # symbol is the one that actually worked. this is C# 8 and C# 9
Using C# we can do string check like if string.contains() method, e.g.:
string test = "Microsoft";
if (test.Contains("i"))
test = test.Replace("i","a");
This is fine. But what if I want to replace a string which contains " symbol to be replaced.
I want to achieve this:
"<html><head>
I want to remove the " symbol present in check so that the result would be:
<html><head>
The " character can also be replaced, just like any other:
test = test.Replace("\"","");
Also, note that you don't have to test if the character exists : your test.Contains("i") could be removed since the .Replace() method won't do anything (no replace, no error thrown) if the character doesn't exist inside the string.
To include a quote symbol in a string, you need to escape it, using a backslash. In your example, you want to use something lik this:
if (test.Contains("\""))
There are two ways to include a '"' character in a string literal. All the answers so far have used the c-style way:
var quotation = "Parting is such sweet sorrow";
var howSweetIsIt = quotation + " that I shall say \"good-night\" till it be morrow.";
In some contexts (especially for users experienced with Visual Basic), the verbatim string literal may be easier to read. A verbatim string literal begins with an # sign, and the only character that requires escaping is the quotation mark -- all other characters are included verbatim (hence the name). Significantly, the method of escaping the quotation mark is different: rather than preceding it with a backslash, it must be doubled:
var howSweetIsIt = quotation + " that I shall say ""good-night"" till it be morrow.";
string SymbolString = "Micro\"so\"ft";
The string above use scape char \ to insert " between the characters
string Result = SymbolString.Replace("\"", string.Empty);
With the following replace I replace the character "" for empty.
This is what you try to achieve?
if (check.Contains("\"")
output = check.Replace("\"", "");
output = check.Replace("\"", "");
Just remember to use "\"" for the quote sign as the backslash is an escape character.
if (str.Contains("\""))
{
str = str.Replace("\"", "");
}
((string)dt.Rows[i][1]).Replace("'", "\\'")
I want the result that if any string have quote it change it into slash quote, e.g. John's -> John\'s
but the above replace function is not working fine.
it results like John\\'s
but if we change the code to
((string)dt.Rows[i][1]).Replace("'", "\'")
it gives the Result like John's
does change it anyway.
Because the backslash is the escape character, you need to tell it you want to treat it like a literal string. You do this by prepending an # to the string:
((string)dt.Rows[i][1]).Replace("'", #"\'")
Try a double backslash.
\\
Just one backslash is an escape; two is an actual backslash.
Use "\\'" or #"\'" for the replacement string. The backslash is the escape character in C# string literals. See the explanation of string literals in C#: \' in a string literal results in just a single quote.
The reason this escape sequence exists, is because single quotes would require escaping if you were using a char literal ('\'').
The # indicates that you're using verbatim string syntax, which allows for multi-line strings and eliminates the need to escape characters, apart from double quote, which you would escape with double double quotes (Visual Basic style).
Can you clarify please? Are you saying that
((string)dt.Rows[i][1]).Replace("'", "\\'")
does not replace a ' with \' ?
Because I just tried it and it works fine. I.e. this
string one = "blah'";
string two = one.Replace("'", "\\'");
Console.WriteLine(two);
Prints blah\'
Replace("'", "\'") use double slash
You could use something like this:
private static string replace(String input)
{
return Regex.Replace(input, "('|\")", "\\'");
}
static void Main(string[] args)
{
String value1 = "John Steve's";
String value2 = "John Steve\"s";
Console.WriteLine(replace(value1));
Console.WriteLine(replace(value2));
}
Results:
John Steve\'s
John Steve\'s
If you want to prepare an SQL query, I think the best method is to replace a single ' for ''. For instance, if you wanto to search John O'Connor, this would work (at least in SQL Server, Access, Oracle, ...).
select ... from users where username = 'Jonh O''Connor'
The following code generates a compiler error about an "unrecognized escape sequence" for each backslash:
string foo = "D:\Projects\Some\Kind\Of\Pathproblem\wuhoo.xml";
I guess I need to escape backslash? How do I do that?
You can either use a double backslash each time
string foo = "D:\\Projects\\Some\\Kind\\Of\\Pathproblem\\wuhoo.xml";
or use the # symbol
string foo = #"D:\Projects\Some\Kind\Of\Pathproblem\wuhoo.xml";
Try this:
string foo = #"D:\Projects\Some\Kind\Of\Pathproblem\wuhoo.xml";
The problem is that in a string, a \ is an escape character. By using the # sign you tell the compiler to ignore the escape characters.
You can also get by with escaping the \:
string foo = "D:\\Projects\\Some\\Kind\\Of\\Pathproblem\\wuhoo.xml";
var foo = #"D:\Projects\Some\Kind\Of\Pathproblem\wuhoo.xml";
If your string is a file path, as in your example, you can also use Unix style file paths:
string foo = "D:/Projects/Some/Kind/Of/Pathproblem/wuhoo.xml";
But the other answers have the more general solutions to string escaping in C#.
string foo = "D:\\Projects\\Some\\Kind\\Of\\Pathproblem\\wuhoo.xml";
This will work, or the previous examples will, too. #"..." means treat everything between the quote marks literally, so you can do
#"Hello
world"
To include a literal newline. I'm more old school and prefer to escape "\" with "\\"