// 隐藏电话的中间四位

 echo parseMobile('15836365252');

 function parseMobile($mobile, $start = 4, $len = 4){

     $firstLen = $start - 1;

     $lastLen = 11 - $len - $firstLen;

     $preg = '/(\d{'.$firstLen.'})(\d{'.$lastLen.'})/';

     return preg_replace($preg, '$1****$3', $mobile);

 }

 // 验证邮箱格式是否正确

 echo checkEmail('aaa.bbb@163.com');

 function checkEmail($mail){

     $bool = false;

     if(strlen($mail) >= 8 && strlen($mail) <= 40 && (strpos($mail,'@') !== false) && (strpos($mail,'.') !== false)){

         $preg = '/^([a-z0-9]+)([a-z0-9_\\.\\-]*)([a-z0-9]+)@([a-z0-9]+)([a-z0-9_\\.\\-]*)([a-z0-9]+)(\\.)([a-z]{2,5})$/i';

         preg_match($preg, $mail) AND $bool = true;

     }

     return $bool;

 }

 // 隐藏IP地址的后面两段

 echo parseIp('192.168.115.210');

 function parseIp($ip){

     $preg = '/(\d+).(\d+).(\d+).(\d+)/';

     return preg_replace($preg, '$1.$2.***.***', $ip);

 }