如何将从循环获得的值赋给数组

Question

I want to assign or store the values I get from foreach loop into an array, so that I can use array sort function for the values. Please below is my code. It seems to create a whole new array for every loop with key = 0. And if i place the print statement below the loop, it will display only the last value obtained from the loop. I don't understand how it was explained in This Question

<?php  

  $studen_id = $this->db->get_where('student' , array('class_id' => $class_id))->result_array();
    foreach($studen_id as $row){
    $mark_obtained = $this->crud_model->get_exam_total($row2['exam_id'] , $class_id , $row['student_id']);

        $student_mark = array($mark_obtained);

        // rsort($student_mark);

        echo "<li>";  print_r($student_mark);  echo "</li>";

    }
?>

Output

Answer 1

You need to add [] to generate proper array. Try this:

<?php  
  $studen_id = $this->db->get_where('student' , array('class_id' => $class_id))->result_array();
  $student_mark = array();
  foreach($studen_id as $row){
    $mark_obtained = $this->crud_model->get_exam_total($row2['exam_id'] , $class_id , $row['student_id']);
    $student_mark[] = $mark_obtained;
  }
?>