contoh 1

gistfile1.php

<?php

$arr = [
	'a' => [
		0=>[
		'file_name'=>'abc',
		'file_type'=>'image/jpeg',
		],
		1=>[
		'file_name'=>'def',
		'file_type'=>'image/jpeg',
		]
	]
];
print_r($arr);
$arr=add_product_num($arr,2);
print_r($arr);

function add_product_num($array,$product_num){
	foreach($array['a'] as $key=>$rows){
		$rows['product_num'] = $product_num;
		$array['a'][$key]=$rows;
	}
	
	return $array;
}