Array to string conversion error in Codeigniter

Question

I'm trying to display an average result from the database to the view but I keep getting this error:

A PHP Error was encountered

Severity: Notice

Message: Array to string conversion

Filename: views/resultview.php

Line Number: 38

Here is the code from the Controller:

$average['avg'] = $this->quiz->getAverage($quizid);

$this->load->view('resultview',array('quiz' => $quiz,
                                     'score' => $score, 
                                     'average_score' => $average));

The function from the model is the following:

   function getAverage($quiz) 
    {
    //get percentage from the database 

    $this->db->select_avg('score');
    $this->db->where('id', $quiz);
    $res = $this->db->get('userScoreQuiz');

    if ($res->num_rows() != 1) {
        // there should only be one row - anything else is an error
        return false;
    }
    return $res->result_array();
}

and the code from the view it is:

<h4> Avg. score on all previous attempts: <?php echo $average_score['avg'] ?>   %</h4> 

I can't seam to find out why it does this.

Thank you for your help guys.

Answer 1

function getAverage($quiz) 
{
    //get percentage from the database 

    $this->db->select_avg('score');
    $this->db->where('id', $quiz);
    $res = $this->db->get('userScoreQuiz');

    if ($res->num_rows() != 1) {
        // there should only be one row - anything else is an error
        return false;
    }
    return $res->row()->score;
}

from docs :

$this->db->select_avg('age');
$query = $this->db->get('members'); // Produces: SELECT AVG(age) as age FROM members

Answer 2

That's too much of coding you got going on, Here is an Elegant solution:

function getAverage($quiz)
{
    //get percentage from the database
    $query = $this->db->select('AVG(score) as average_score')->from('userScoreQuiz')->where('id', $quiz)->get();
    return $query->row()->average_score;
}

For your view

$data['quiz']          = //fill this area
$data['average_score'] = $this->quiz->getAverage($quizid);
$data['score']         = //fill this area

$this->load->view('resultview', $data);

And they will be accessable as $quiz, $average_score, $score

Answer 3

replace the

echo $average_score['avg'];

to

print_r($average_score['avg'];

because that not one variable, that is set of array

Answer 4

codeigniter result_array() returns data as array. And array index starts with 0 index.

"$average_score['avg']" this should be undefined index. Try to access result array as $average_score['avg'][0]['score'] if you don't want to change in your function.

if you want to avoid extra array index then return results using row() instead on result_array().