preg_match():
<?php
$str 
"1978,Dérick,Rethans";
if (
preg_match('@,(.{6}),@'$str$result)) {
    echo 
'We matched: '$result[1], "<br/>\n";
} else {
    echo 
'There was no match!'"<br/>\n";
}
?>
Output:
There was no match!




preg_match() in UTF-8 mode:
<?php
$str 
"1978,Dérick,Rethans";
if (
preg_match('@,(.{6}),@u'$str$result)) {
    echo 
'We matched: '$result[1], "<br/>\n";
} else {
    echo 
'There was no match!'"<br/>\n";
}
?>
Output:
We matched: Dérick