/^([a-z0-9])(([-a-z0-9._])*([a-z0-9]))*\@([a-z0-9])*(\.([a-z0-9])([-a-z0-9_-])([a-z0-9])+)*$/i

<?php

$mail = 'abcdedf@abc12.com';

$pattern = '/^([a-z0-9])(([-a-z0-9._])*([a-z0-9]))*\@([a-z0-9])*(\.([a-z0-9])([-a-z0-9_-])([a-z0-9])+)*$/i';

preg_match($pattern, $mail, $matches);

var_dump($matches);

?>

/^(1(([35][0-9])|(47)|[8][0126789]))\d{8}$/

$text = '15812345678';

$search ='/^(1(([35][0-9])|(47)|[8][0126789]))\d{8}$/';

if(preg_match($search,$text)) {

 echo '手机完全符合';

}