Pull data from wordpress database - unknown format

I need help pulling data from the field with unknown format of data structure. I am using a wordpress quiz plugin and i want to pull data from its backend table. Data stored in answer_data is:

a:4:{
i:0;O:27:"WpProQuiz_Model_AnswerTypes":7:{s:10:"*_answer";s:17:"Kieran Trippier ";s:8:"*_html";b:0;s:10:"*_points";i:1;s:11:"*_correct";b:0;s:14:"*_sortString";s:0:"";s:18:"*_sortStringHtml";b:0;s:10:"*_mapper";N;}

i:1;O:27:"WpProQuiz_Model_AnswerTypes":7:{s:10:"*_answer";s:11:"Hugo Lloris";s:8:"*_html";b:0;s:10:"*_points";i:1;s:11:"*_correct";b:0;s:14:"*_sortString";s:0:"";s:18:"*_sortStringHtml";b:0;s:10:"*_mapper";N;}

i:2;O:27:"WpProQuiz_Model_AnswerTypes":7:{s:10:"*_answer";s:14:"Moussa Dembele";s:8:"*_html";b:0;s:10:"*_points";i:1;s:11:"*_correct";b:0;s:14:"*_sortString";s:0:"";s:18:"*_sortStringHtml";b:0;s:10:"*_mapper";N;}

i:3;O:27:"WpProQuiz_Model_AnswerTypes":7:{s:10:"*_answer";s:14:"Jan Vertonghen";s:8:"*_html";b:0;s:10:"*_points";i:1;s:11:"*_correct";b:1;s:14:"*_sortString";s:0:"";s:18:"*_sortStringHtml";b:0;s:10:"*_mapper";N;}
}

while looking at the structure of the table, data type of answer_data is longtext but has utf8_general_ci alongside it. I dont know what this means. From this data i want to pull, quiz answers i.e.Kieran Trippier,Hugo Lloris,Moussa Dembele and Jan Vertonghen. Any help or hint will be very much appreciated.

EDIT 1:

Array ( 
[0] => WpProQuiz_Model_AnswerTypes Object ( [_answer:protected] => Kieran Trippier [_html:protected] => [_points:protected] => 1 [_correct:protected] => [_sortString:protected] => [_sortStringHtml:protected] => [_mapper:protected] => ) 
[1] => WpProQuiz_Model_AnswerTypes Object ( [_answer:protected] => Hugo Lloris [_html:protected] => [_points:protected] => 1 [_correct:protected] => [_sortString:protected] => [_sortStringHtml:protected] => [_mapper:protected] => ) 
[2] => WpProQuiz_Model_AnswerTypes Object ( [_answer:protected] => Moussa Dembele [_html:protected] => [_points:protected] => 1 [_correct:protected] => [_sortString:protected] => [_sortStringHtml:protected] => [_mapper:protected] => ) 
[3] => WpProQuiz_Model_AnswerTypes Object ( [_answer:protected] => Jan Vertonghen [_html:protected] => [_points:protected] => 1 [_correct:protected] => 1 [_sortString:protected] => [_sortStringHtml:protected] => [_mapper:protected] => ) )

how to get values from this array?

Solution

That is some form of serialization. It seems to be an array a of 4 elements, each of which is further structure. The plugin understands; you probably don't need to understand it.

utf8_general_ci is the "Collation" to be used for comparing the LONGTEXT strings. It implies CHARACTER SET utf8, which is the 3-byte subset of UTF-8 (aka, MySQL's utf8mb4). This allows you to include characters from most languages around the world.

One would hope that the plugin provides a way to dissect this structure, rather than leaving you guessing. Furthermore, the plugin could change the structure without notice.

Here's the hint: See PHP's serialize() and unserialize().

Using the unserialized result:

$foo seems to be an array of 'objects' of class WpProQuiz_Model_AnswerTypes. One of the 'properties' of that object seems to be $_answer. So, see if this gives you the list of answers:

foreach($foo as $obj) {
    echo $obj->_answer, "\n";
}

Or, to grab the answers into an array $answers:

$answers = array();
foreach($foo as $obj) {
    $answers[] = $obj->_answer;
}