title: check $_GET request if isset by its key
body: <p>I have this URL</p>
  
  <pre><code>www.domain.com/page.php?odor[type]=black&amp;odor[shape]=cube
  </code></pre>
  
  <p>How do i check if the <code>$_GET</code> request <code>isset()</code> by the keys? just something like</p>
  
  <pre><code>if(isset($_GET['odor[type]'])){
      echo $odor['type']
  }
  </code></pre>