Sorting an array by a certain key

Question

I have the following array:

Array
(
    [Places] => Array
        (
            [public] => 0
            [entities] => Array
                (
                    ...
                )
        )
    [Issues] => Array
        (
            [public] => 1
            [entities] => Array
                (
                    ...
                )
        )

    [Source] => Array
        (
            [public] => 0
            [entities] => Array
                (
                    ...
                )
        )
)

I would like to be able to sort by the array by the public key. I know I may have to use either ksort or usort but I am unsure on how to implement this.

Any ideas would be great thanks!

Answer 1

usort($array, function ($a, $b) { return $a["public"] - $b["public"]; });

Answer 2

take a look at this, using array_multisort :

$test   =   array(
        'Places' => array(
            'public' => 0,
            'entities' => array(

            )
        ),
        'Issues' => array(
            'public' => 1,
            'entities' => array()
        ),
        'Source' => array(
            'public' => 0,
            'entities' => array()
        )
    );

    echo '<pre>';
    print_r($test);
    echo '</pre>';

    array_multisort($test,SORT_ASC,$test);

    echo '<pre>';
    print_r($test);
    echo '</pre>';

Answer 3

Here's an interesting link: http://www.the-art-of-web.com/php/sortarray/

I would try a

usort(usort(array, function), function);

I can try a sample code upon request, but the information is already there for the taking.

Answer 4

The general way to do this using array_multisort is to place your sorting value into its own array and then sort both arrays using that as the primary sorting array.

Try the following:

$test   =   array(
    'Places' => array(
        'public' => 0,
        'entities' => array(

        )
    ),
    'Issues' => array(
        'public' => 1,
        'entities' => array()
    ),
    'Source' => array(
        'public' => 0,
        'entities' => array()
    )
);

echo '<pre>';
print_r($test);
echo '</pre>';

$sort = array();
foreach ($test as $k => $a) {
    $sort[$k] = $a['public'];
}

// placing $sort first in array_multisort causes $test to be sorted in same order as the values in $sort
array_multisort($sort,SORT_ASC,$test);

echo '<pre>';
print_r($test);
echo '</pre>';

Answer 5

You could use usort with callback function.

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

usort($array, "cmp");

Answer 6

Try this:

$code = "return (-1*strnatcmp(\$a['public'], \$b['public']));";
uasort($array, create_function('$a,$b', $code));