How to replace <pubdate> RSS FEED

Question

I'm trying to create RSS FEED This feed does not validate. From

<pubDate><?php echo $topNewest->data['last_update'] ?></pubDate>

echo <pubDate>2012-10-02 13:00:00</pubDate>

I want replace element must be an RFC-822 date-time

<pubDate>Wed, 02 Oct 2002 13:00:00 GMT</pubDate>

Answer 1

Use the DateTime class in php which has RFC822 built in

 $d = new DateTime($topNewest->data['last_update']);
 echo $d->format(DateTime::RFC822);

You can change the format if you need, look at php.net/date