Question

I have an array that looks like this:

Array ( [0] => Array ( [filters] => Array ( [filter_1] => 1 
                                            [filter_2] => 1 
                                            [filter_3] => 1 
                                            [filter_4] => 1 
                                            [filter_5] => 1 
                                            [filter_6] => 1 ), 
                       [count]   => 2),

        [1] => Array ( [filters] => Array ( [filter_1] => 1 
                                            [filter_2] => 1 
                                            [filter_3] => 1 
                                            [filter_4] => 1 
                                            [filter_5] => 1 
                                            [filter_6] => 1 ), 
                       [count]   => 34)

        [2] => Array ( [filters] => Array ( [filter_1] => 1 
                                            [filter_2] => 1 
                                            [filter_3] => 1 
                                            [filter_4] => 1 
                                            [filter_5] => 1 
                                            [filter_6] => 1 ), 
                        [count]   => 7)

Is it possible to sort the main array keys by the [count] key in each, descending? So that they are in the following order: 1 -2 -0

Answer 1

You definitely want the usort function. You can define how the sort function determines which is larger or smaller.

If it’s alright that each sub-array (of “filters” and “count”) gets re-indexed, this should work perfectly. By re-indexed, I mean the newly sorted array would start at 0, progress to 1, etc. This is almost always how you want it, unless your original array is associative.

For example:

usort($array, "byCount");

function byCount($a, $b)
{
    if( $a['count'] == $b['count'] )
    {
        return 0;
    }
    return ($a['count'] < $b['count']) ? -1 : 1;
}