3v4l.org

run code in 300+ PHP versions simultaneously
<?php $data = array ( 'rows' => array ( 0 => array ( 'position' => 1, 'image_id' => 2809, 'basename' => 'rj5ed2c90f609423.26673093.jpg' ), 1 => array ( 'position' => 1, 'image_id' => 2808, 'basename' => 'rj5ed2c8eccc9c06.91700011.jpg' ), 2 => array ( 'position' => 2, 'image_id' => 2807, 'basename' => 'rj5ed2c77ef32b76.96579137.jpg' ) ) ); $data['rows'] = array_reduce($data['rows'], function ($c, $a) { $c[$a['position']][] = $a; return $c; }, array()); print_r($data);
Output for 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
Array ( [rows] => Array ( [1] => Array ( [0] => Array ( [position] => 1 [image_id] => 2809 [basename] => rj5ed2c90f609423.26673093.jpg ) [1] => Array ( [position] => 1 [image_id] => 2808 [basename] => rj5ed2c8eccc9c06.91700011.jpg ) ) [2] => Array ( [0] => Array ( [position] => 2 [image_id] => 2807 [basename] => rj5ed2c77ef32b76.96579137.jpg ) ) ) )

preferences:
148.26 ms | 410 KiB | 5 Q