这是什么数据格式？解决思路

这是什么数据格式？
a:24:{s:8:"duration";i:900;s:8:"redoable";s:2:"20";s:8:"onebyone";s:1:"0";s:7:"answers";s:1:"1";s:13:"given_answers";s:1:"1";s:17:"shuffle_questions";s:1:"1";s:15:"shuffle_answers";s:1:"1";s:17:"general_threshold";i:50;s:12:"master_score";i:50;s:11:"random_pool";i:0;s:17:"user_configurable";i:0;s:16:"maintain_history";s:1:"5";s:12:"display_list";s:1:"0";s:10:"pause_test";s:1:"1";s:15:"display_weights";s:1:"1";s:12:"only_forward";s:1:"0";s:10:"answer_all";s:1:"0";s:10:"redo_wrong";i:0;s:8:"redirect";s:1:"0";s:13:"assign_to_new";N;s:20:"automatic_assignment";N;s:20:"show_answers_if_pass";s:1:"1";s:15:"show_incomplete";i:0;s:13:"test_password";i:0;}

数据格式
------解决方案--------------------
序列化之后的格式，可用unserialize() 还原。
------解决方案--------------------
php 序列化数据

$s = <<< TXT<br />
a:24:{s:8:"duration";i:900;s:8:"redoable";s:2:"20";s:8:"onebyone";s:1:"0";s:7:"answers";s:1:"1";s:13:"given_answers";s:1:"1";s:17:"shuffle_questions";s:1:"1";s:15:"shuffle_answers";s:1:"1";s:17:"general_threshold";i:50;s:12:"master_score";i:50;s:11:"random_pool";i:0;s:17:"user_configurable";i:0;s:16:"maintain_history";s:1:"5";s:12:"display_list";s:1:"0";s:10:"pause_test";s:1:"1";s:15:"display_weights";s:1:"1";s:12:"only_forward";s:1:"0";s:10:"answer_all";s:1:"0";s:10:"redo_wrong";i:0;s:8:"redirect";s:1:"0";s:13:"assign_to_new";N;s:20:"automatic_assignment";N;s:20:"show_answers_if_pass";s:1:"1";s:15:"show_incomplete";i:0;s:13:"test_password";i:0;}<br />
TXT;<br />
<br />
print_r(unserialize($s));

Array
(
    [duration] => 900
    [redoable] => 20
    [onebyone] => 0
    [answers] => 1
    [given_answers] => 1
    [shuffle_questions] => 1
    [shuffle_answers] => 1
    [general_threshold] => 50
    [master_score] => 50
    [random_pool] => 0
    [user_configurable] => 0
    [maintain_history] => 5
    [display_list] => 0
    [pause_test] => 1
    [display_weights] => 1
    [only_forward] => 0
    [answer_all] => 0
    [redo_wrong] => 0
    [redirect] => 0
    [assign_to_new] => 
    [automatic_assignment] => 
    [show_answers_if_pass] => 1
    [show_incomplete] => 0
    [test_password] => 0
)