title: Variable Validation in Laravel
body: <p>I need to know how I can vaildate a variable in Laravel. 
  Until now, I only used <code>$request</code> for validation in this way.</p>
  
  <pre><code>$request-&gt;validate([
      'idgroup' =&gt; [
          'required',
          'numeric',
          new AdminGroupRequest,
          new MaxInvitationAdmin
      ]
  ]);
  </code></pre>
  
  <p>How can I use this validation code above for the following variable?</p>
  
  <pre><code>$idgroup = Session::get('invitation_userid');
  </code></pre>