title: If statement With One equals sign and Two Question Marks - PHP
body: <p>Just looking at the index.php page in Symfony 4. Just wondered if someone could clarify what this means?</p>
  <pre><code>if ($trustedHosts = $_SERVER['TRUSTED_HOSTS'] ?? false) {
      Request::setTrustedHosts([$trustedHosts]);
  }
  </code></pre>
  <p>I'm thinking this this equivalent to the following but not sure thanks.</p>
  <pre><code>if(isset( $_SERVER['TRUSTED_HOSTS'] )){
  
     $trustedHosts = $_SERVER['TRUSTED_HOSTS'];
     Request::setTrustedHosts([$trustedHosts]);
    
  }
  </code></pre>