Collection sum

Ruby
1

Hello,

I really like the ability to do sums right in the object model, for
example

@items.sum(:unit_price), etc! works great!

However I wonder how you step down through an association to do a sum

current_user.carts.first.cart_items.items.sum(:unit_price)

Finding the users first cart works fine but the collection to collection
between cart_items to items doesn’t.

TIA

GP

2

This sounds like a Rails question, and you may want to ask it on a
Rails-specific list; also, its hard to tell what may be going on
without knowing the definition of the objects being used. With the
most intuitive layout of objects for what you seem to be doing, I’d
expect what you are looking for to be something like
current_user.carts.first.items.sum(:unit_price).