title: Filter array by first letter
body: <p>I'm building a platform. Somewhere in my code, there's an array that looks like this (PHP):</p>
  
  <pre><code>$entries = array('p01','p02','g01','g02','a001','a002')
  </code></pre>
  
  <p>I need to write a script that filters the array based on the first letter. For example, asking for those with the starting letter "p" would give me</p>
  
  <pre><code>$filtered_entries = array('p01','p02');
  </code></pre>
  
  <p>Similarly, if I asked for those with starting letter "g" or "a" it would give me those as well. Any idea how to accomplish this?</p>