Sort rows of a 2d array by a column descending

Question

How do I sort an array with the highest points?

Example:

$sale = array();

Array
(
   [UserA] => Array
        (
            [unsuccessful] => 0
            [Points] => 31
            [procesing] => 4
        )
   [UserB] => Array
        (
            [unsuccessful] => 4
            [Points] => 200
            [procesing] => 1
        )
   [UserC] => Array
        (
            [unsuccessful] => 3
            [Points] => 150
            [procesing] => 55
        )
)

Sort by points, it should be in order: UserB, UserC, UserA

Answer 1

uasort($array, function($a, $b) {
    return $b['Points'] - $a['Points'];
});

The uasort() and usort() functions take a callback that should specify exactly what makes one item greater or lower than another item. If this function returns 0, then the items are equal. If it returns a positive number, then the second item is greater than the first item. Else, the first item is greater than the second.

The difference between uasort() and usort() is that uasort() also keeps the keys, while usort() does not. Also take a look at the comparison of array sorting functions to find out about all the other ways you can sort arrays.