/** * @param string $type * @param $length * @return string */function randomstring($type=number,upper,lower,$length){ $valid_type = array('number','upper','lower'); $case = explode(,,$type); $count = count($case); //根据交集判断参数是否合法 if($count !== count(array_intersect($case,$valid_type))){ return false; } $lower = abcdefghijklmnopqrstuvwxyz; $upper = strtoupper($lower); $number = 0123456789; $str_list = ; for($i=0;$i $str_list .= $$case[$i]; } return substr(str_shuffle($str_list),0,$length);}echo randomstring(number,upper,lower,12);
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