日付に曜日をつけたい時(例:2010/04/30)とか。
<?php
function date_opt($string) {
$wd = array(日,月,火,水,木,金,土);
$date = explode("/", $string);
$pwd = $wd[date("w", mktime(0, 0, 0, $date[1], $date[2], $date[0]))];
$postpat = '#^\d{4}/\d{2}/\d{2}#';
$pt_opt = '$0(' . $pwd . ')';
$pattern = postpat;
$replace = pt_opt;
$string = preg_replace($pattern, $replace, $string);
return $string;
}
?>