Comparing arrays inside multidimensional array - php

Question

Basically i want to compare arrays inside a multidimensional array,
So i want to compare everyone with etc category 1 against each other, category 2 against earch other etc etc.
So what i really want to do is:
Compare every category against each other with this formula
versus - won = x
And then find out who has the lowest number and then update that last survivor from each category in the database (The winners)
Any ideas on how i can solve this the best?
$arr;
$stmt = $dbCon->prepare(" SELECT versus, won, imgId, category FROM rating_versus ");
$stmt->execute();
$stmt->bind_result($versus, $won, $imgId, $category);
while ($stmt->fetch()) {
$arr[] = array('category' => $category, 'id' => $imgId, 'versus' => $versus, 'won' => $won);
// echo $imgId . "<br> Versus: " . $versus . "<br> Won: " . $won . "<br> <br>";
}
$stmt->close();
This will output something like this
array(9) {
[0]=> array(4) { ["category"]=> int(1) ["id"]=> int(1) ["versus"]=> int(42) ["won"]=> int(21) }
[1]=> array(4) { ["category"]=> int(1) ["id"]=> int(5) ["versus"]=> int(47) ["won"]=> int(24) }
[2]=> array(4) { ["category"]=> int(1) ["id"]=> int(13) ["versus"]=> int(47) ["won"]=> int(23) }
[3]=> array(4) { ["category"]=> int(2) ["id"]=> int(2) ["versus"]=> int(45) ["won"]=> int(19) }
[4]=> array(4) { ["category"]=> int(2) ["id"]=> int(4) ["versus"]=> int(49) ["won"]=> int(25) }
[5]=> array(4) { ["category"]=> int(2) ["id"]=> int(7) ["versus"]=> int(44) ["won"]=> int(25) }
[6]=> array(4) { ["category"]=> int(3) ["id"]=> int(3) ["versus"]=> int(47) ["won"]=> int(29) }
[7]=> array(4) { ["category"]=> int(3) ["id"]=> int(6) ["versus"]=> int(50) ["won"]=> int(18) }
[8]=> array(4) { ["category"]=> int(3) ["id"]=> int(9) ["versus"]=> int(45) ["won"]=> int(24) }
}

Answer 1

To find the winner, you don't need to eliminate one by one, who has the lowest score.
Winner is who has the highest score.
So your code should be like following
$arr; $stmt = $dbCon->prepare(" SELECT versus, won, imgId, category FROM rating_versus ");
$stmt->execute();
$stmt->bind_result($versus, $won, $imgId, $category);
$winners=array();
while ($stmt->fetch()) {
$arr[] = array('category' => $category, 'id' => $imgId, 'versus' => $versus, 'won' => $won);
if(isset($winners[$category])) {
$curmax = $winners[$category]['won'];
if($won>$curmax) {
$winners[$category] = array('id'=>$imgId, 'won' => $won);
}
} else {
$winners[$category] = array('id'=>$imgId, 'won' => $won);
}
// echo $imgId . "<br> Versus: " . $versus . "<br> Won: " . $won . "<br> <br>";
}
$stmt->close();
print_r($winners);
This should work for this case