title: Regular expression to find URLs within a string
body: <p>Does anyone know of a regular expression I could use to find URLs within a string? I've found a lot of regular expressions on Google for determining if an entire string is a URL but I need to be able to search an entire string for URLs.  For example, I would like to be able to find <code>www.google.com</code> and <code>http://yahoo.com</code> in the following string:</p>
  
  <pre class="lang-none prettyprint-override"><code>Hello www.google.com World http://yahoo.com
  </code></pre>
  
  <p>I am not looking for specific URLs in the string. I am looking for ALL of the URLs in the string which is why I need a regular expression.</p>