title: using preg_replace to keep a part of a string with php
body: <p>I have the following string.</p>
  
  <pre><code>http://www.sample.com/profile/272353.html
  </code></pre>
  
  <p>I will like to use preg_replace to keep this part of the string.</p>
  
  <pre><code>profile/272353.html
  </code></pre>
  
  <p>The first part of the string changes so I just want to make sure to leave that part of the strng.</p>
  
  <p>I am new to patterns and I still don't get it so any help would be appreciated.</p>