PHP array problem

Wouldn't it just be easier to keep your array sorted by number of same answers? Maybe even just add the new person, resort the array and remove the first/last..

Sounds like you could solve this in SQL very easily, but will require a great deal of work to do in PHP.

You need to sort the entries according to the delta to person.number_of_answers. Eg.:

function cmp_by_delta($a, $b) {
  if ($a->delta == $b->delta) {
    return 0;
  }
  return ($a->delta < $b->delta) ? -1 : 1;
}
// calculate delta for each entry
foreach ($entries as $person) {
  $person->delta = abs($target_person->number_of_answers - $person->number_of_answers);
}
// sort entries by delta
usort($entries, 'cmp_by_delta');
// take 10 first matches from sorted array
$10_best_matches = array_slice($entries, 0, 10);

Of course, this can be done much prettier and much more efficiently in a database:

select * from people
order by abs(number_of_answers - :target_number_of_answers)
limit 10;