如何在php中获取特定的数组值

我想从php中的数组输出一个特定的值

下面是我的代码和数组 $content

输出显示如下:

Array ( [currency] => INR 
[shipping] => 0 
[tax] => 0 
[taxRate] => 0 
[itemCount] => 3 
[item_name_1] => Our Nest 
[item_quantity_1] => 1 
[item_price_1] => 1900 
[item_options_1] => image: CF01108.jpg, productcode: 602793420 
[item_name_2] => Our Nest 
[item_quantity_2] => 1 
[item_price_2] => 2100 
[item_options_2] => image: CF01110.jpg, productcode: 123870196 
[item_name_3] => Our Nest 
[item_quantity_3] => 1 
[item_price_3] => 1800 
[item_options_3] => image: CF01106.jpg, productcode: 416267436 )

如何productcode在php变量中获取值并回显它？

例:

602793420,123870196,416267436