The PHP sequence number generates the function and string replacement function code

 
/** 
*  Serial number generator  
*/ 
function snMaker($pre = '') { 
$date = date('Ymd'); 
$rand = rand(1000000,9999999); 
$time = mb_substr(time(), 5, 5, 'utf-8'); 
$serialNumber = $pre.$date.$time.$rand; 
// echo strlen($serialNumber).'<br />'; 
return $serialNumber; 
} 
echo snMaker(); 
/** 
*  will 1 Of a string 1 Replace the part with something 1 Specific character  
* @param str or int $str  The string that needs to be processed  
* @param str or int $to  What string will it be replaced with  
* @param int $start  Keep the first few characters  
* @param int $end  Keep the last few characters  
*/ 
function hideString($str = 'hello', $to = '*', $start = 1, $end = 0) { 
$lenth = strlen($str) - $start - $end; 
$lenth = ($lenth < 0) ? 0 : $lenth; 
$to = str_repeat($to, $lenth); 
$str = substr_replace($str, $to, $start, $lenth); 
return $str; 
} 
echo hideString();