Best way to trim zip codes

[Ghosty]

I've got some hyphenated zip codes as values in an array and I need to dump the hyphen (and everything after the hyphen). Is trim() the best function for this?

[mudshark]

Probably not the most efficient, but seems to do the job:

<?php
$a = array('1234-456', '9874-412');
function strip_hyphen($s){
    $bits = explode('-', $s);
    return $bits[0];
}
$new = array_map('strip_hyphen', $a);
print_r($new);
?>

[UFTimmy]

$new_zip = substr( $old_zip, 0, 5 );