The second example - a recommendation system
A recommendation system recommends a product or a service to a customer based on the products/services he has bought/used and in the products/services bought/used by the users that have bought/used the same services as him.
We have used the example explained in the previous section to implement a recommendation system. Each description of a product includes the reviews of a number of customers to a product. This review includes the score the customer gives to the product.
In this example, you will use these reviews to get a list of the products that may be interesting to a customer. We will obtain the list of the products purchased by a customer. In order to get that list, a list of the users who have purchased those products and the list of products purchased by those users are sorted using the average score given in the reviews. That will be the suggested products for the user.
Common classes
We have added two new classes to the ones used in the...
