PHP的array_multisort不工作

Question

I'm having this issue where I want to sorty a multidimensional array based on 2 parameters

I build my array like this:

$teamList[$t['id']] = array(
    'id'     => $t['id'], 
    'name'   => $t['name'], 
    'score'  => $score, 
    'points' => $array
);

I then sort like this:

foreach ($teamList as $key => $row) {
        $score[$key]  = $row['score'];
        $points[$key] = $row['points'];    
}
array_multisort($score, SORT_DESC, $points, SORT_DESC, $teamList);  

But the $teamList remains unsorted?

Answer 1

You can easily use a user defined compare function instead of doing all the copying of values and abusing array_multisort() .

function sortByScoreAndPoints($a, $b) {
  if ($a['score'] == $b['score']) {
    if ($a['points'] == $b['points']) {
      return 0;
    }
    return ($a['points'] > $b['points']) ? -1 : 1;
  }
  return ($a['score'] > $b['score']) ? -1 : 1;
}

uasort($teamlist, 'sortByScoreAndPoints');

The sort function has to accept two parameters which can have arbitrary names, but $a and $b is used in the docs. During sorting, PHP passes any two values of the array as $a and $b and expects an answer in which order they should appear. Your sort function has to return -1 if $a should appear first, 0 if they are equal, or 1 if $a should appear last, compared to $b.

My code first tests if the scores are equal. If not, the last return will compare which score is higher ( $a > $b ), and the highes score goes into the list first (if a is bigger than b, return -1 to say a goes first).

If the scores are equal, points will be tested. If they are not equal, the comparison takes place again. Otherwise 0 is returned.

Any entry in the team list with equal score and points might appear in arbitrary location in the result (but not random - the same input array will always be sorted the same), because there is no further ordering specified. You might easily extend your sorting by adding another comparison for the name or the id, if you like.

If you want your sorted array to be renumbered starting at 0, use usort() instead of uasort() .