Online PHP editor | output for C7uBJ

<?php function check($str){ if(preg_match('#^869\d{11}$#', $str)) { $arr = str_split(substr($str, 0,13)); $even = $odd = $num = 0; foreach ($arr as $key => $value) { if($key % 2 == 0) { $even += $value; } else { $odd += $value; } } $even *= 3; $num = $even + $odd; $num = strval($num); $res = $num{strlen($num) -1}; if($res == 0 && $str[13] == 0) { return '匹配成功'; } else if ($str[13] == (10 - $res)) { return '匹配成功'; } else{ return '匹配失败'; } } else{ return '匹配失败'; } } echo check('8691234554321');