PHP代码 生成随机字符串，去除0oi1z2容易混淆字符

    function  mm($len=8){
        global  $db;
        $str = 'ABCDEFGHJKLMNPQRSTUVWXY3456789';
        $randstr = '';
        for ($i = 0; $i < $len; $i++) {
            $randstr .= $str[mt_rand(0, strlen($str) - 1)];
        }
            return $randstr;
 
    }