Question : php str_replace question

The output of the array ['location'] is always state, city and zip:
<?=niceLabel(str_replace(',', ', ', $listing['location']), false)?>

So the output of the code above is:
North Jackson,  OH 44451

What I would like to do is to remove City and State  so the only output will be the Zip Code only:
44451

Answer : php str_replace question

Assuming that the zipcode is always 5 numbers long, and preceeded by a space, this works:

$string="Anywhere, OH 12345";
$zip = substr($string,strrpos($string," ")+1,5);
echo $zip;