title: E-mail address validation using Regular Expressions
body: <p>I'm writing a simple, small app that allows me to share information. I have a question on using regx to validate email address.
  I'm kind learning on my own. But when it comes to real-world examples, such that strings that can be validated with regular expressions, I'm kind stuck.</p>
  
  <p>Exercise: 
  Untangle the following regular expression that validates an email address:</p>
  
  <pre><code>  [a-z0-9!#$%&amp;'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&amp;'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?
  </code></pre>
  
  <p>It looks like a jumble of characters. </p>
  
  <p>Can someone please explain to me how does this work? </p>
  
  <p>I try to use this online resources by by <a href="http://www.regular-expressions.info/email.html" rel="nofollow">Jan Goyvaerts.</a> 
  Any help I will appreciate it. </p>