title: How do I extract ID's from this array without making an unnecessary DB call?
body: <p>In my controller I have extracted all the files that are in trashcan like this:</p>
  
  <pre><code>@myfiles = Myfile.all.where("user_id = ? AND trashcan = ?", current_user.id, 1).order('created_at DESC')
  </code></pre>
  
  <p>How do I fetch all the ID's of the myfiles that have been collected?</p>