Iterate through array_keys

Client Joined: Oct 07, 2003 Posts: 735 Location: Ohio

I have a page that displays correct answers to an exam. It shows a frequency count of answers, and the correct frequency count was bold. I need to add another column and add the correct answer in the form of the letter, (a,b,c,d,e). My problem lies in the fact that sometimes I have more than one correct answer, or the teacher will throw a question out and give everybody credit, meaning all answers are correct. I'm having trouble displaying this as it is passed to a template and the page said array in the column.

In the beginning $stat_points looks like this. 0#1#0#0#0#, which means "b" is correct answer.

Here is what I'm doing.

Code:

$stat_points = $stats['points']; 


$raw_points = explode ( "#", $stat_points);                       


array_pop($raw_points); // last element will always be empty because the points seperated by # and also end with #

So I end up like 01000 right?

I then do the following for my different question types.

Code:

if ($stats['qtype'] == 1) {


$letters = array("a", "b", "c", "d", "e");


}elseif ($stats['qtype'] == 4){


    $letters = array("a", "b", "c", "d", "e", "f", "g", "h", "i");


}

Then I combine the two.

Code:




$array_haystack = array_combine($letters, $raw_points);

At one point I was trying this but could not get it to display correctly.

Code:




$needle = 1;


$correct_answer = array_keys($array_haystack, $needle);

Then I tried something like

Code:

while (list($key, $val) = each($array_haystack)) {


   


   if($val == 1) { 


   $correct_answer = $key; 


   }


         


}

But still could not get those question with more than one answer to display correctly.

How do I get this working so that I can pass it to my template?

Code:

$template -> assign_block_vars('stats', array('QNO' => $stats['ques_order'], 'QTITLE' => $stats['ques_name'], 'QDBNO' => $stats['ques_id'], 'BGCOLOR' => $color,


                                             'WHOLE' => $stats['whole'], 'UPPER' => $stats['upper25'], 'LOWER' => $stats['lower25'],


                                             'DISCRIM' => round((float)($stats['discri']),2),                                             


                                             'CORRECT' => $correct_answer,


                                                      


                                             'AFREQ' => $freq[0], 'BFREQ' => $freq[1], 'CFREQ' =>$freq[2], 'DFREQ' => $freq[3], 'EFREQ' =>$freq[4], 'FFREQ' =>$freq[5], 'GFREQ' =>$freq[6], 'HFREQ' =>$freq[7], 'IFREQ' =>$freq[8], 'SUM' => $sum


                        ));

registered · Posted: Thu Oct 07, 2010 7:54 pm

You are on the right track with the loop (there are multiple ways of doing it, but this while loop is fine too):

Quote:

while (list($key, $val) = each($array_haystack)) {

if($val == 1) {
$correct_answer = $key;
}

}

The problem is that you keep overlaying your $correct_answer variable! Instead, why not create an empty array before the while, and every time you get a hit on the "1", add another array element for the answer letter. Then, outside the while loop, use implode() to join it all back together in a comma separate string?

Wink

Posted: Fri Oct 08, 2010 7:38 am

So you think something like this?

Code:

$array_haystack = array_combine($letters, $raw_points);


      


reset($array_haystack);


unset($correct_answer);


unset($key);





$correct_answer = array(); 


while (list($key, $val) = each($array_haystack)) {


   


   if($val == 1) {   


   array_push($correct_answer, $key);    


   }      


}


$correct_answers = explode(",", $correct_answer);

Posted: Sat Oct 09, 2010 12:29 pm

Well, you don't have to use array_push(), a simple $correct_answer[] = $key would have worked too. Wink

But your last line there, I said you needed to use implode() not explode().