文字列から数値を抜き出す｜PHP

<?php

//---

	$string = "wlakjd1113ww";

	$search = "/[^0-9]/";

	$replacement = "";

	echo preg_replace($search,'$replacement',$string);

	-

//---

	-

?>

<?php

//---

	-

	-

//---

	-

?>