在PHP中按多个键对数组进行排序

Question

I have a table/array. E.g. in Excel I can sort by column 1 asc, column 2 desc, column 3 asc, etc.

Can I do same in PHP? First with ["first_name"] ASC, then ["last_name"] DESC, ["player_id"] ASC and ["user_id"] DESC.

array(2) {
    [0]=> array(6) {
        [0]=> string(8) "John",
        ["first_name"]=> string(8) "John",
        [1]=> int(7) "44",
        ["score"]=> int(7) "44",
        [2]=> string(2) "7",
        ["player_id"]=> string(2) "7",
        [3]=> string(2) "3",
        ["user_id"]=> string(2) "3"
    },
    [1]=> array(6) {
        [0]=> string(5) "Sam",
        ["first_name"]=> string(5) "Sam",
        [1]=> int(7) "55",
        ["score"]=> int(7) "55",
        [2]=> string(2) "1",
        ["player_id"]=> string(2) "1",
        [3]=> string(2) "6",
        ["user_id"]=> string(2) "61"
    }
}

(The array is much longer and deeper in reality, this is just an example.)

Update:

function byPlayerID($player, $compare) {
    if($player['player_id'] > $compare['player_id'])
        return 1; // move up
    else if($player['player_id'] < $compare['player_id'])
        return -1; // move down
    else
        return 0; // do nothing

    if($player['score'] > $compare['score'])
        return 1; // move up
    else if($player['score'] < $compare['score'])
        return -1; // move down
    else
        return 0; // do nothing
}

Update 2: Never mind, I just needed to remove return 0;

Answer 1

Use usort().

Example:

$byPlayerID = function($player, $compare) {
  if($player['player_id'] > $compare['player_id'])
    return 1; // move up
  else if($player['player_id'] < $compare['player_id'])
    return -1; // move down
  else
    return 0; // do nothing
};

usort($players, $byPlayerID);
// now $players is sorted!

This does require PHP 5.3 though, below is a more backwards compatible version

function byPlayerID($player, $compare) {
  if($player['player_id'] > $compare['player_id'])
    return 1; // move up
  else if($player['player_id'] < $compare['player_id'])
    return -1; // move down
  else
    return 0; // do nothing
}

usort($players, "byPlayerID");