从数组中检索值时遇到问题

I am facing issue to retrieve value following array. Please let me know how i can get that.I want to get the first value '[_answer]'

  WpProQuiz_Model_AnswerTypes Object
  (
   [_answer:protected] => new1
   [_html:protected] => 
   [_points:protected] => 1
   [_correct:protected] => 
   [_sortString:protected] => 
   [_sortStringHtml:protected] => 
   [_mapper:protected] => 
 )

  Basically i am trying to getting data from serialize data and after unserialize it is showing above output:

   a:4:{i:0;O:27:"WpProQuiz_Model_AnswerTypes":7:  {s:10:"*_answer";s:4:"new1";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:4:"new2";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;}i:2;O:27:"WpProQuiz_Model_AnswerTypes":7:{s:10:"*_answer";s:4:"new3";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:4:"new4";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;}}

This is an object, not an array. You have two ways to access the propertys of it.

You can use echo WpProQuiz_Model_AnswerTypes->_answer

or you cast it to an array like this

$asArray = (array)WpProQuiz_Model_AnswerTypes;
echo $asArray['_answer'];