Online PHP editor | output for 5imCm

<?php $input = [ ["relation" => "OR"], ["color" => 'green'], ["color" => 'yellow'], ["relation" => "AND"], ["color" => 'black'], ["color" => 'orange'], ["relation" => "OR"], ["color" => 'blue'], ["color" => 'violet'], ]; $ref = []; $result = &$ref; foreach ($input as $row) { if (key($row) === 'relation') { if ($ref) { // not the first relation encountered $ref = &$ref[]; // set $ref to point to new deeper subarray } $ref = $row; // push relation } else { $ref[] = $row; // push color into reference } } var_export($result);