Aaron Aaron - 3 months ago 9
PHP Question

Sorting array by count of subarray

I have an array looking like this:

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'))


And I want to sort the array by the number of values of that has the names, In my case I want to become this array:

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


This means sorting categories by name by the number(count) of values of the names. Someone can help me?
Thanks in advance,

AƤron

Answer

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
                )

        )

)