Counting lines in a string

Great analysis!

I found out that Regex can be accelerated by a factor of about two.

Instead of

new Regex(@"\n", RegexOptions.Compiled|RegexOptions.Multiline);

you can speed up by using:

new Regex(@"^.*?$", RegexOptions.Compiled|RegexOptions.Multiline);

But admittedly, nothing beats the native methods (IndexOf).

[EDIT]
My statement above is wrong: I did compare "$" (and not "\n") against "^.*?".
The measurments show that "\n" is the fastest of all Regex matches, while "$" is the slowest (5 times slower than "\n"...!).
That's a real surprise to me.

The comparison:

Regex Match	[ms] for 2.500.000 lines	RegexOptions
\n	1847	Compiled|Singleline
\n	1851	Compiled|Multiline
^.*$	2282	Compiled|Multiline
^.*?$	5327	Compiled|Multiline
$	10100	Compiled|Multiline

As a comparison: IndexOf('\n') only takes 237 [ms].

[/EDIT]