I would like to compactly insert a <br /> tag before every line break in a string with regular expressions in C#. Can this be done? Currently, I am only able to replace the line break with the following:
myString = Regex.Replace(myString, @"\r\n?|\n", "<br />");
Can I modify this to include the matched text (i.e. either \r\n, \r, or \n) in the replacement?
Clearly, it can be done with a separate Match variable, but I'm curious if it can be done in one line.
Use parentheses to capture the line break, and use $1 to use what you captured in the replace:
myString = Regex.Replace(myString, @"(\r\n?|\n)", "<br />$1");
$& to write back the entire match. also the OP wanted to insert the tag before the line break ;)
MSDN has a separate page just for .NET's regex substitution magic.
While the others are correct that the most general approach is to capture something and write back the captured contents with $n (where n is the captured group number), in your case you can simply write back the entire match with $&:
myString = Regex.Replace(myString, @"\r\n?|\n", "<br />$&");
If you are doing this a lot then avoiding the capturing could be a bit more efficient.
You can do this with a substitution in your "replace" string:
Regex.Replace(myString, @"(\r\n?|\n)", "$1<br />");
