title: Extract substring after a certain pattern
body: <p>I have the following string:</p>
  
  <pre><code>http://xxx/Content/SiteFiles/30/32531a5d-b0b1-4a8b-9029-b48f0eb40a34/05%20%20LEISURE.mp3?&amp;mydownloads=true
  </code></pre>
  
  <p>How can I extract the part after <code>30/</code>? In this case, it's <code>32531a5d-b0b1-4a8b-9029-b48f0eb40a34</code>.I have another strings having same part upto 30/ and after that every string having different id upto next / which I want.</p>