Comments on: Advanced Regular Expressions in C#

By: Ravi

Ravi — Fri, 21 Jan 2011 06:45:47 +0000

Excellent post. Working on Regular expressions in .net. Found it helpful as a novice to start learning the Regular expressions.

By: Tod Birdsall

Tod Birdsall — Fri, 04 Jun 2010 19:49:23 +0000

Excellent article. The Conditional String Replacement section was exactly what I was looking for. Thanks.

By: Zoon

Zoon — Fri, 26 Mar 2010 12:37:29 +0000

I’ve been using Regular Expressions for just about anything. I always knew they were a bit slower but never like 40 times slower!! Next time I’ll consider simple string operations before going the regex way!

Good article btw!

By: Holystream

Holystream — Fri, 02 Oct 2009 17:14:36 +0000

Just noticed Richard said the same thing

By: Holystream

Holystream — Fri, 02 Oct 2009 16:50:45 +0000

Because we have added a lot of spaces and new lines to our expression we need to tell Regex about them by specifying the RegexOptions.Multiline and RegexOptions.IgnorePatternWhitespace options.

This is incorrect. RegexOptions.Multiline changes the behavior of the matching against the target string. It does not have anything to do with breaking the regular expression into multiple lines. For example, if your option is RegexOptions.Singleline, then ^ matches the start of the entire string, $ matches the end of the entire string, while in RegexOptions.Multiline, ^ matches start of the beginning of the line after the last carriage return, and $ matches before the carriage return.

All you need is RegexOptions.IgnorePatternWhitespace, if you broke your regular expression into multiple lines.

By: paul heintz

paul heintz — Thu, 27 Aug 2009 11:24:02 +0000

Excellent, I’ve used them for years and yes after coming back to my code to modify many a time have I crossed my eyes trying to remember why and what I did.

This is extremely helpful at structuring code

Thank you,

By: Martin Sykora

Martin Sykora — Mon, 15 Jun 2009 17:49:31 +0000

Wow, this is a sweet little intro to regex, good blog writing my friend!

Keep it up!! I am looking forward to other topics you will cover

By: Link Love | Kaeli's Space

Link Love | Kaeli's Space — Sun, 12 Apr 2009 13:44:19 +0000

[...] Advanced Regular Expressions in C# – neat tricks, including how to comment the expression [...]

By: Richard

Richard — Fri, 13 Mar 2009 17:34:13 +0000

“Because we have added a lot of spaces and new lines to our expression we need to tell Regex about them by specifying the RegexOptions.Multiline and RegexOptions.IgnorePatternWhitespace options.”

RegexOptions.Multiline doesn’t do what you think it does. Rather than specifying that the pattern is on multiple lines, it changes the meaning of ^ and $ so they match at the beginning and end, respectively, of any line, and not just the beginning and end of the entire string.

RegexOptions.IgnorePatternWhitespace is enough to tell the engine to ignore the white-space – including new-lines – within your pattern.

By: Gareth

Gareth — Thu, 12 Mar 2009 14:42:53 +0000

I like to learn something every day. And I never knew you could use “#” to comment regular expressions in conjunction with RegexOptions.IgnorePatternWhitespace. Thanks!