Sort an array by a child array's value in PHP

You can make use of usort function as:

$arr = array(
                array("105945","First name",0.080878465391),
                array("109145","Second name",0.0504154818384)
            );

function cmp($a, $b) {
        if ($a[2] == $b[2]) {
                return 0;
        }
        return ($a[2] < $b[2]) ? -1 : 1;
}

usort($arr,"cmp");

As of PHP >= 7.0 you can use usort in combination with the spaceship operator

usort($arr, function ($a, $b) {
        return $a[2] <=> $b[2];
    });

see: http://php.net/manual/de/migration70.new-features.php

For database like patterns use array_multisort as seen in example #3.

For example:

$sort = array();
foreach ($data as $key => $row) {
  $sort[$key]  = $row['basis'];
}
array_multisort($sort, SORT_ASC, $data);

where $data is your data array and basis is the element used for sorting.