PHP how to find array value from string post - php

Question

Using PHP & codeigniter.
I posting below to my PHP api
submitting from front end - > {"academicYear":"2015","subjectClassification":"Primary","subjectId":"55","teacherId":[10,16,17]}
I need to find or print teacherId values in my PHP code.
Basically my target is to print "HELLO" 3 time if there is 3 Id in teacherId array.
My code look like below,
function subjectTeacherAllocation_post(){
$data = remove_unknown_fields($this->post() ,$this->form_validation->get_field_names('subjectTeacherAllocation_post'));
$this->form_validation->set_data($data);
var_dump($data);
$teacherList = array($data['teacherId']);
echo $teacherList[0];
echo array_values($teacherList);
var_dump output --> array(3) { ["academicYear"]=> string(4) "2014" ["subjectId"]=> string(2) "55" ["teacherId"]=> array(3) { [0]=> int(9) [1]=> int(15) [2]=> int(32) } }

Answer 1

You are needlessly wrapping $data['teacherId'] in an extra array, instead just do:
$teacherList = $data['teacherId'];
echo $teacherList[0]; //9
Specifically, to produce hello x number of times, where x is the number of elements in the above $teacherList array:
foreach($teacherList as $unused){
echo 'hello';
}