Sorting array by count of subarray

Question

I have an array looking like this:

Array(
   [\'some_first_category\'] => Array(
            [\'some_first_name\'] => Array(
                                   


        

Answer 1

All you need is uasort

uasort($list, function ($a, $b) {
    $a = count($a);
    $b = count($b);
    return ($a == $b) ? 0 : (($a < $b) ? -1 : 1);
});

Full Example

$list = Array(
   'some_first_category' => Array(
            'some_first_name' => Array(
                           0=>'first@email.com',
                           1=>'second@email.com',
                           2=>'third@email.com',
                           3=>'fourth@email.com' ),
             'some_second_name' => Array (
                           1=>'first@email.com',
                           2=>'second@email.com'),
             'some_third_name' => Array(
                           1=>'first@email.com',
                           2=>'second@email.com',
                           3=>'third@email.com',
                           4=>'fourth@email.com' )
        ),
   'some_second_category' => Array(
            'some_first_name' => Array(
                           0=>'first@email.com' ),
             'some_second_name' => Array(
                           1=>'first@email.com',
                           2=>'second@email.com',
                           3=>'third@email.com',
                           4=>'fourth@email.com'),
             'some_third_name' => Array(
                           1=>'first@email.com',
                           2=>'second@email.com'))

    );

$list = array_map(function ($v) {
    uasort($v, function ($a, $b) {
        $a = count($a);
        $b = count($b);
        return ($a == $b) ? 0 : (($a < $b) ? 1 : - 1);
    });
    return $v;
}, $list);


print_r($list);

Output

Array
(
    [some_first_category] => Array
        (
            [some_first_name] => Array
                (
                    [0] => first@email.com
                    [1] => second@email.com
                    [2] => third@email.com
                    [3] => fourth@email.com
                )

            [some_third_name] => Array
                (
                    [1] => first@email.com
                    [2] => second@email.com
                    [3] => third@email.com
                    [4] => fourth@email.com
                )

            [some_second_name] => Array
                (
                    [1] => first@email.com
                    [2] => second@email.com
                )

        )

    [some_second_category] => Array
        (
            [some_second_name] => Array
                (
                    [1] => first@email.com
                    [2] => second@email.com
                    [3] => third@email.com
                    [4] => fourth@email.com
                )

            [some_third_name] => Array
                (
                    [1] => first@email.com
                    [2] => second@email.com
                )

            [some_first_name] => Array
                (
                    [0] => first@email.com
                )

        )

)

Answer 2

Using uksort:

uksort($yourArray, function($a, $b) { return count($b) - count($a); });

Using array_multisort:

array_multisort(array_map('count', $yourArray), SORT_DESC, $yourArray);

and you can see uasort as well

best of luck :)

Answer 3

You should use usort function. Refer here.

function sort_sub($a,$b)
{
$res= count($b)-count($a);
return $res;
}

usort($array_name,'sort_sub')