How to exclude an array of id's from a find-method? - arrays

Question

I'm calling an array of recommended products (based on the predictor-gem) and want to exclude the products of the current_user from that set. I think that I'm using the proper condition for it (" != ?") but just not in the correct way. #products_rec should give that final array.
Here's the specific code in my product_controller.rb:
recommender = ProductRecommender.new
products = current_user.products
#product_rec = (recommender.similarities_for("product-#{#product.id}")).map {|el| el.gsub(/(.*\-)[^\d]*/, "")}
#products_rec = Product.find(#product_rec, :conditions => ["id != ?", products.id])
and here's my model, product.rb:
class Product < ActiveRecord::Base
include Reviewing
include PublicActivity::Model
tracked
extend FriendlyId
friendly_id :name, use: [:slugged, :finders]
belongs_to :category
belongs_to :benefit
has_many :subscriptions
has_many :users, through: :subscriptions
has_many :benefits
has_many :projects, through: :benefits
belongs_to :user
validates :name, presence: true, length: { maximum: 200 }
validates :gtin, presence: false
validates :content, presence: false, length: { maximum: 2000 }
validates :video, presence: false
validates :tag, presence: false
validates :project, presence: false
validates :category, presence: false
validates :user, presence: false
has_attached_file :image, :styles => { :medium => "680x300>", :thumb => "170x75>" }
validates_attachment_content_type :image, :content_type => /\Aimage\/.*\Z/
end
I want to exclude the products from the current_user, based on the users through subscriptions (see model).
How can I get this to work, any ideas?
Final code:
Based on the answer of #Humza, I've added the following working code to my product_controller.rb:
recommender = ProductRecommender.new
products = current_user.products.select("id")
#product_rec = (recommender.similarities_for("product-#{#product.id}")).map {|el| el.gsub(/(.*\-)[^\d]*/, "")}
#products_rec_array = Product.find(#product_rec)
#products_rec = Product.where(id: #products_rec_array).where.not(id: products)

Answer 1

To find products with id not in array, you must do this:
array = current_user.products.pluck(:id)
Product.where('id NOT IN (?)', array) # '?' is surrounded by paranthesis
But since a product belongs to a user, you can simply do
Product.where('user_id != ?', current_user.id)
You can also use the not method like so:
Product.where.not(id: array)
Product.where.not(user_id: current_user.id)
Edit:
If you want the base products to be from some other list, this can help:
base_product_ids = some_list.map(&:id) # assuming this is an Array
Product.where(id: base_product_ids).where.not(user_id: current_user.id)
If some_list was an ActiveRecord::Relation, you could have simply done:
some_list.where.not(user_id: current_user.id)