Regex to uppercase between delimiters

Question

I am looking for a regex that looks for any $$some_val$$ and replaces the some_val with uppercase letters.

For example the input is:-

<p><a href='accept/272/$$id$$'>YES</a></p>
<p>Hi $$FirstName$$ some more text $$date$$ lorem ipsum</p>
<h1>$$club$$</h1>
$$content$$

would output:-

<p><a href='accept/272/$$ID$$'>YES</a></p>
<p>Hi $$FIRSTNAME$$ some more text $$DATE$$ lorem ipsum</p>
<h1>$$CLUB$$</h1>
$$CONTENT$$

at the moment I have the following regex:-

var html = Regex.Replace(html, @"\$\$(.*)\$\$", m=> m.Value.ToUpper());

but it produces the incorrect result.

<p><a href='accept/272/$$ID$$'>YES</a></p>
<p>Hi $$FIRSTNAME$$ SOME MORE TEXT $$DATE$$ lorem ipsum</p>
<h1>$$CLUB$$</h1>
$$CONTENT$$

as the SOME MORE TEXT is also capitalised between the start and end $$ delimiters.

Please note that $$ might reoccur in a line OR start/end on a line.

Answer 1

You just need to use the non-greedy/lazy match quantifier ( *? ):

var regex = new Regex(@"\$\$.*?\$\$");
var input = "this $$is a$$ test of the $$procedure$$";
var output =
     r.Replace(input, m=>m.Value.ToUpper());

Answer 2

try this , it should works :

var html = Regex.Replace(html, @"\$\$(.\w*)\$\$", m=> m.Value.ToUpper());

i have test it on : http://rubular.com/r/YRI3WrzXAu

Answer 3

You need to use the lazy *? instead of the eager * . * by itself tries to match as much as possible, *? tries to match as little as possible.

var html = Regex.Replace(html, @"\$\$(.*?)\$\$", m=> m.Value.ToUpper());

Answer 4

Another option could be to use a lookahead assertion. For example:

var html = Regex.Replace(html, @"\$\$(?:[^$]|\$(?!\$))*\$\$", m => m.Value.ToUpper());

This would search for the two dollars, then search for anything that is not a dollar OR a dollar that is not succeeded by another dollar. Greediness in this case would not matter due to the lookahead assertion.

This is a bit more advanced than the dot-star you've been using, so if dot-star works for you, then it may be more realistic to stick with that.