sort array by sub arrray values?

I'm trying to figure out the best way to sort an array. This is what the array looks like:

Array
(
    [11687] => Array
        (
            [passed] => 2
            [failed] => 4
        )

    [8545] => Array
        (
            [passed] => 1
            [failed] => 0
        )

    [1631] => Array
        (
            [passed] => 12
            [failed] => 16
        )

    [2251] => Array
        (
            [passed] => 1
            [failed] => 1
        )
)

PHP:

I'm trying to sort it by the sum of passed and failed. So the order would end up like this: 1631,11687,2251,8545.

Any ideas?

 

Loop over the values, and create 2 (or 3, if necessary) arrays. One array holding all "passed" values, and one holding all "failed" values.

Then use array_multisort() and you're done.

 

You could use usort() and define a custom sorting function. The only trouble with that is it assigns new array keys. That isn't really a problem if you run it on a copy of your array though.

Here is how that would look:

<?php

$test = Array
(
    11687 => Array
        (
            'passed' => 2,
            'failed' => 4
        ),

    8545 => Array
        (
            'passed' => 1,
            'failed' => 0
        ),

    1631 => Array
        (
            'passed' => 12,
            'failed' => 16
        ),

    2251 => Array
        (
            'passed' => 1,
            'failed' => 1
        )
);

// Add another key (alongside 'passed' and 'failed') to save the key numbers - usort assigns new keys, removing any existing ones
while (list($key, $value) = each($test)) {
  $test[$key]['key'] = $key;
}

echo "Before...<br>\n";
reset($test);
while (list($key, $value) = each($test)) {
    echo "$key ";
}

usort($test, "cmp");

reset($test);
echo "<br>After...<br>\n";
while (list($key, $value) = each($test)) {
    echo $test[$key]['key']." ";
}

function cmp($a, $b) {
    if (($a['passed']+$a['failed']) == ($b['passed']+$b['failed'])) {
        return 0;
    }
    return (($a['passed']+$a['failed']) > $b['passed']+$b['failed']) ? -1 : 1;
}

?>

PHP:

 

Actually, you can use UASORT instead of USORT and eliminate all that process of having to store the keys and reassign them.

I've also made the compare function shorter, and I stored it in a variable using the create_function() method since it's really only a disposable function that you're only going to need to sort the array so no point in having a full function for it.

<?php

$test = Array
(
    11687 => Array
        (
            'passed' => 2,
            'failed' => 4
        ),

    8545 => Array
        (
            'passed' => 1,
            'failed' => 0
        ),

    1631 => Array
        (
            'passed' => 12,
            'failed' => 16
        ),

    2251 => Array
        (
            'passed' => 1,
            'failed' => 1
        )
);

print "Unsorted:<br />";

print_r($test);

$sort_function = create_function('$a,$b', 'return ($b[\'passed\'] + $b[\'failed\']) - ($a[\'passed\'] + $a[\'failed\']);');
uasort($test, $sort_function);

print "<br />Sorted:<br />";
print_r($test);

?>

PHP:

 

Indeed, much neater. Nice work zerxer.

 

Thanks, works great!