title: How to use preg_match to extract data?
body: <p>I am pretty new to the use of preg_match. Searched a lot for an answer before posting this question. Found a lot of posts to get data based on youtube ID etc. But nothing as per my needs. If its silly question, please forgive me.</p>
  
  <p>I need to get the ID from a string with preg_match. the string is in the format</p>
  
  <pre><code>[#1234] Subject
  </code></pre>
  
  <p>How can I extract only "1234" from the string?</p>