PHP: Calculate Score by Category

[skrafft74]

I'm fairly new to PHP and trying to sort a class project. I've banged away and can't see to sort it out, this is the last remaining piece.

I have a form - submit essentially 2 arrays I'm trying to determine the average score for based upon the category groupings. 1. ($_post['category']), ($_post['score']) - with category being a text based array and score obviously being numbers based.

How would I go about finding the average score for each category? I've tried various options to for mapping the two arrays and then trying to average the grades. I can get the total score average pretty easily, but finding a ways to do this by each category individually is tripping me up.

I need to apply a weight to each category score, but that seems pretty easy once you get the above sorted.

Thanks, Steve

$_POST example:

Array (
[0] => Assignment
[1] => Assignment
[2] => Assignment
[3] => Assignment
[4] => Assignment
[5] => Assignment
[6] => Exam
[7] => Assignment
[8] => Assignment
[9] => Assignment
[10] => Exam
[11] => Exam
[12] => Final Project
)
Array (
[0] => 100
[1] => 100
[2] => 100
[3] => 98
[4] => 90
[5] => 92
[6] => 100
[7] => 100
[8] => 100
[9] => 100
[10] => 100
[11] => 92
[12] => 100
)

[akphidelt2007]

I would create an array by category with the scores. Sort of like this

$scores = Array('Assignment'=>Array(),'Exam'=>Array(),'Final Project'=>Array());
 
foreach($_POST['categories'] as $index => $category)
{
  $scores[$category][] = $_POST['scores'][$index];
}
 
//now you will have an array like
//$scores['Assignment'] = Array('score1','score2','score3')
 
//loop through to get the totals
foreach($scores as $cat => $array)
{
   $count = count($array);
   $sumOfScores = array_sum($array);
   $average = $count > 0 ? $sumOfScores/$count : 0;
 
   echo "Category: $cat has $count scores and an average score of $average<br>";
}

Edited April 28, 2013 by akphidelt2007

[skrafft74]

Thanks akphidelt, that's the piece I've been trying to figure out.

 

foreach($_POST['categories'] as $index => $category)
{
  $scores[$category][] = $_POST['scores'][$index];
}

 

 

I knew I wanted to map the two arrays together, but wasn't really sure of the syntax.