3v4l.org

run code in 500+ PHP versions simultaneously
<?php $arr1 = array( 0 => ['product_type'=>'manufacturer','id'=>1], 1 => ['product_type'=>'manufacturer','id'=>2], 2 => ['product_type'=>'seller'], 3 => ['product_type'=>'seller'], 4 => ['product_type'=>'seller'], 5 => ['product_type'=>'seller'], 6 => ['product_type'=>'seller'], 7 => ['product_type'=>'manufacturer','id'=>3], ); $manuCounter = 0; $sellerCounter = 0; $result = []; foreach ($arr1 as $row) { if ($row['product_type'] === 'manufacturer') { $manuCounter += 4; $result[$manuCounter] = $row; } else { ++$sellerCounter; if (!($sellerCounter % 4)) { ++$sellerCounter; } $result[$sellerCounter] = $row; } } ksort($result); var_export(array_values($result));

preferences:
85.88 ms | 1517 KiB | 5 Q