How to loop through multi-dimentional array in PL/PGSQL

Hello,

Please help me in accessing multi-dimentional array in postgresql
PL/PGSQL.

for i in array_lower(product_list, 1) .. array_upper(product_list, 1)
LOOP
product_list[i][0];
END LOOP;

Is the above code right?

Or is there any other way to access, i am getting null for
product_list[i][0];

Any help would be appreciated.

--
Regards :
Venktesh Guttedar.