* 把数字替换成*

 * @param int    $head    头部显示数字长度

 * @param int    $tail    尾部显示数字长度

 * @param string    $num    要替换的字符

 * author feng

 *

function digitalReplacedAsterisk($head, $tail, $num){

return substr($num,0,$head).str_replace(array(0,1,2,3,4,5,6,7,8,9),'*',substr($num,$head,(strlen($num)-$head-$tail))).substr($num,-$tail);

}