php正则的使用[替换，匹配]

 1 // 隐藏电话的中间四位
 2 echo parseMobile('15836365252');
 3 function parseMobile($mobile, $start = 4, $len = 4){
 4     $firstLen = $start - 1;
 5     $lastLen = 11 - $len - $firstLen;
 6     $preg = '/(d{'.$firstLen.'})(d{'.$lastLen.'})/';
 7     return preg_replace($preg, '$1****$3', $mobile);
 8 }
 9 
10 // 验证邮箱格式是否正确
11 echo checkEmail('aaa.bbb@163.com');
12 function checkEmail($mail){
13     $bool = false;
14     if(strlen($mail) >= 8 && strlen($mail) <= 40 && (strpos($mail,'@') !== false) && (strpos($mail,'.') !== false)){
15         $preg = '/^([a-z0-9]+)([a-z0-9_\.\-]*)([a-z0-9]+)@([a-z0-9]+)([a-z0-9_\.\-]*)([a-z0-9]+)(\.)([a-z]{2,5})$/i';
16         preg_match($preg, $mail) AND $bool = true;
17     }
18     return $bool;
19 }
20 
21 // 隐藏IP地址的后面两段
22 echo parseIp('192.168.115.210');
23 function parseIp($ip){
24     $preg = '/(d+).(d+).(d+).(d+)/';
25     return preg_replace($preg, '$1.$2.***.***', $ip);
26 }