I've thought about writing this post several times over the past two years.  Having had regular expressions come up three times last week, I thought it time to address the lack of programmers out there who understand regular expressions.  The sheer amount of fear surrounding regular expressions and the work that goes into avoiding them is astonishing.

Last year I used to troll around the asp.net forums and quite frequently I would answer the regex questions.  One question was posted which illustrates the problem with regexes among developers.

"...and i also i need to add a validator for the password textbox where the user is required to fill atleast [sic] 6 characters"

I suggested a solution to the problem using a regular expression validator. Making sure there are at least 6 characters, is a simple regex (example: \w{6,}), and yet my solution was met with skepticism.  The following was said, in the event a change was requested,

"Putting a new version of a web site can take a surprising amount of time than can go into man-weeks". 

Man-weeks?!?!?  To change a regular expression?!?!?  I see two problems, first the original developer who didn't know that regex would easily solve their problem.  The second problem is the other developer who doesn't know regex advocating his way as "the way", in effect, spreading his ignorance.  The first developer is easily forgiven, the second is not.

It's been said programmers can't program when faced with a simple FizzBuzz test, Imran states:

"Want to know something scary? - the majority of comp sci graduates can’t. I’ve also seen self-proclaimed senior programmers take more than 10-15 minutes to write a solution."

I'll pile on.  You want to know something scary?  The majority of professional programmers can't write regular expressions, even simple ones.  I'm not the first to say this.  Last year, at the ALT.NET conference, Scott Guthrie made the following statement when talking about routes in the new MVC framework:

"It's pluggable, so you can use Regexes...<some incoherent stuff>...if you wanna use regexes you can.  What we found is, regexes are super powerful, but only about 10% of people actually understand 'em."

Are regular expressions easy to understand? Well, let me ask you, was HTML easy when you started?  Were you born understanding the following HTML?

<fieldset class="CheckRadio">
    <div id="OngoingEventContainer">
        <input type="checkbox" id="OngoingEvent" name="OngoingEvent" value="1" />
        <label for="OngoingEvent">
            This is an ongoing event (no dates and times)
        </label>
    </div>
</fieldset>

If you understand the above, you didn't always.  My guess is that at some point you buckled down and learned HTML because you're job requires it.  Well, if you're a programmer, web or windows, you need to know regular expressions, your job requires it, it's that simple. 

Regular expressions have been around so long that they're deeply ingrained in many of the tools we use.  Christopher Bennage illustrates how regular expressions solved a recent problems in Visual Studio.  In a recent post he posts:

"Then I realized that I was missing the simple solution. Ctrl+F and a regular expression!"

I don't know that many people would be able to come to the conclusion that Christoper did.  It's my belief that regular expressions are fundamental, yet the average developer doesn't treat them as such.  They're ultimately doing themselves a disservice.

Regular Expressions are a tool that should be in every programmers bag.  If you don't understand regular expressions and do a google search every time you need a regular expression, shame on you!  It's time to bite the bullet and learn regular expressions.