controller logic not working

So I've written this code in my controller and it doesn't seem to
process my records and I don't know why.

error = nil
@my_cart = @user.shopping_cart
@my_cart_items = @user.shopping_cart.shopping_cart_items
for shopping_cart_item in @my_cart_items
   if @quantity > 0
      ....do stuff
   end

end

Is this valid?

Hello--

So I've written this code in my controller and it doesn't seem to
process my records and I don't know why.

error = nil
@my_cart = @user.shopping_cart
@my_cart_items = @user.shopping_cart.shopping_cart_items
for shopping_cart_item in @my_cart_items
  if @quantity > 0
     ....do stuff
  end

end

Is this valid?
--

No. This doesn't look like it should work. I'd really recommend reading up on Ruby a bit. @my_cart_items would appear to be a collection (an array). Using "for" you are iterating over that list but you are not using the individual item yielded by the iterator. So, perhaps what you wanted was:

for shopping_cart_item in @my_cart_items do |item|
   unless item.quantity.zero?
     # do stuff...
   end
end