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up vote 2 down vote favorite

Okay, this one is pretty complicated... lets say I have an array called $data

Array
(
    [9e5b0d6d-711c-4cd0-8697-634a5c640066] => Array
        (
            [player] => 9e5b0d6d-711c-4cd0-8697-634a5c640066
            [wins] => 1
            [loss] => 6
            [winsR] => 2
            [lossR] => 12
        )

    [a8f7fb4c-afab-4ec0-9202-b87fa2641110] => Array
        (
            [player] => a8f7fb4c-afab-4ec0-9202-b87fa2641110
            [wins] => 1
            [loss] => 6
            [winsR] => 2
            [lossR] => 12
        )

    [96ed2f95-08bd-42f8-bb57-9df09b66109d] => Array
        (
            [player] => 96ed2f95-08bd-42f8-bb57-9df09b66109d
            [wins] => 2
            [loss] => 5
            [winsR] => 4
            [lossR] => 10
        )

    [2a4e1a3e-cde4-4c9b-947e-67a4d333f0f4] => Array
        (
            [player] => 2a4e1a3e-cde4-4c9b-947e-67a4d333f0f4
            [wins] => 3
            [loss] => 4
            [winsR] => 6
            [lossR] => 8
        )

    [08c23d63-69a9-4147-b40f-64b241cfbb4f] => Array
        (
            [player] => 08c23d63-69a9-4147-b40f-64b241cfbb4f
            [wins] => 4
            [loss] => 3
            [winsR] => 8
            [lossR] => 6
        )

    [777e8f3e-caac-41fb-975e-a410e42f7114] => Array
        (
            [player] => 777e8f3e-caac-41fb-975e-a410e42f7114
            [wins] => 5
            [loss] => 2
            [winsR] => 11
            [lossR] => 4
        )

    [9cd5256f-6d3a-4bd5-aeed-b6904bcbf048] => Array
        (
            [player] => 9cd5256f-6d3a-4bd5-aeed-b6904bcbf048
            [wins] => 6
            [loss] => 1
            [winsR] => 12
            [lossR] => 3
        )

    [797c95df-c334-4328-a8eb-4ba5e690af4d] => Array
        (
            [player] => 797c95df-c334-4328-a8eb-4ba5e690af4d
            [wins] => 6
            [loss] => 1
            [winsR] => 12
            [lossR] => 2
        )
)

As you can see, I have a series of data, and each element has it's own nested array. I already know I can sort the array using a single nested value using 

usort($data, create_function('$a, $b', 'return $b["wins"] - $a["wins"];'));

However, this is not enough.

The problem is, sorting with the above function doesn't sort deep enough for me. All it does is sort based on the following:

  • ['wins'] DESCENDING (highest wins sorted first)

I would like to sort using FOUR nested values.

  • ['wins'] DESCENDING (highest wins sorted first)
  • ['loss'] ASCENDING (lowest loss sorted second)
  • ['winsR'] DESCENDING (highest winsR sorted third)
  • ['lossR'] ASCENDING (lowest lossR sorted fourth)

I know this is pretty complicated, so I'm coming here to ask for help. What would be the best and most efficient way to do this?

share|improve this question

1 Answer

up vote 3 down vote accepted

What you're looking for is the function usort().

There, you can supply your own comparator that can compare two elements and apply the rules you wish to use.

You were on the right track, but your comparator function can be much more elaborate:

function compare_elements($l, $r) {
    if ($l['wins'] > $r['wins']) {
        return -1;
    } else if ($l['wins'] < $r['wins']) {
        return 1;
    }

    // Drop to second level; it will have exited by here
    // if the tie could be broken by the first rule.
    // You really could've put this in an else clause, but I
    // wanted to avoid excessive nesting.
    if ($l['loss'] > $r['loss']) {
        return 1;
    } else if ($l['loss'] < $r['loss']) {
        return -1;
    }

    // And so on until the 4th level    
}
share|improve this answer
Hmm... very cool... how would I use usort() in a class environment? I cant exactly do usort($data, $this->compare_elements) – Jason Axelrod Jun 1 '12 at 5:31
In a class environment you'd probably either define it as a class-scope function with the static keyword and call that MyClass::compare_ranking_array as the comparator or you can use anonymous functions (see php.net/manual/en/functions.anonymous.php) – phsource Jun 1 '12 at 5:35
Thanks... you da man! – Jason Axelrod Jun 1 '12 at 5:58

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