Online PHP editor | output for kmY30

<?php $arr = array( 0 => array ( 'item_id' => '1', 'store_id' => '1', 'price' => '74.99' ), 1 => array( 'item_id' => '2' , 'store_id' => '1' , 'price' => '35.99' ), 2 => array( 'item_id' => '3' , 'store_id' => '1' , 'price' => '89.99' ), 3 => array( 'item_id' => '1' , 'store_id' => '2' , 'price' => '69.99' ), 4 => array( 'item_id' => '2', 'store_id' => '2', 'price' => '39.99' ), 5 => array( 'item_id' => '3', 'store_id' => '2', 'price' => '95.99' ) ); $output = array(); foreach($arr as $item){ if(in_array($item['item_id'], array_column($output, 'item_id'))){ // add store to already existing item $key = array_search($item['item_id'], array_column($arr, 'item_id')); $output[$key]['store_id_' . $item['store_id']] = $item['price']; }else{ // add new item with store $tmp = array( 'item_id' => $item['item_id'], 'store_id_' . $item['store_id'] => $item['price'], ); $output[] = $tmp; } } echo '<pre>'; print_r($output); ?>