PHP array_multisort

Question

I'm having some difficulties with sorting arrays. I tried with methods SORT_DESC, SORT_NUMERIC but it never works. Even when I put array_multisort anywhere else in the code.

So this is how my arrays looks like:

Array
(
    [0] => Array
        (
            [0] => 0.13
            [1] => Ships From
            [2] => Russia
        )

)
Array
(
    [0] => Array
        (
            [0] => 0.11
            [1] => Color
            [2] => Green
        )

)
Array
(
    [0] => Array
        (
            [0] => 0.1
            [1] => Size
            [2] => M
        )

)
Array
(
    [0] => Array
        (
            [0] => 0.12
            [1] => Material
            [2] => Flex
        )

)
Array
(
    [0] => Array
        (
            [0] => 0.13
            [1] => Ships From
            [2] => China
        )

)
Array
(
    [0] => Array
        (
            [0] => 0.11
            [1] => Color
            [2] => Red
        )

)
Array
(
    [0] => Array
        (
            [0] => 0.1
            [1] => Size
            [2] => L
        )

)
Array
(
    [0] => Array
        (
            [0] => 0.12
            [1] => Material
            [2] => Cotton
        )

) 

As you can see I have double [0], and by that value to sort them all. So my code looks like this:

foreach($value['options'] as $key => $option)
            {
                $sort = array();


                $attribude= $this->attribute($option['key']);
               
                $attribute_value= $this->attribude($getAttr->id, $option['value']);

                $collection = array_push($sort, array($attribude->default_order, $attribude->label, $attribute_value->value));

                print_r($sort);
            }

I tried to add array_multisort($sort, SORT_ASC); basically everywhere where I could, but it's never working. Any ideas how to solve that?

Answer 1

I would suggest, if you can, restructuring your array before attempting to sort. Below is an example of the restructured array sorted by the number 2 index. You can adjust the index by changing this $row[2] like $row[0] to sort by the float value of index zero.

$array = [
    array(0.13,'Ships From','C'),
    array(0.12,'Ships From','D'),
    array(0.10,'Ships From','B'),
    array(0.14,'Ships From','A'),
];

$a = array();
$b = array();
foreach ($array as $key => $row) {
    $a[$key] = $row[2];
}
array_multisort($a, SORT_ASC, $array);

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

Array
(
    [0] => Array
        (
            [0] => 0.14
            [1] => Ships From
            [2] => A
        )

    [1] => Array
        (
            [0] => 0.1
            [1] => Ships From
            [2] => B
        )

    [2] => Array
        (
            [0] => 0.13
            [1] => Ships From
            [2] => C
        )

    [3] => Array
        (
            [0] => 0.12
            [1] => Ships From
            [2] => D
        )

)

Answer 2

An inline solution:

usort($array, function($a, $b) { return $a[0] <=> $b[0]; });

A flagship operator requires PHP 7+, otherwise compare manually. For reverse (DESC) order swap $a with $b.