Overview

Choose whatever language you're most comfortable with to solve these problems.

Exercise

The ACME inc. tool supply company manages its operations with 3 csv files:

1. customers.csv keeps customer information:
   • id is a numeric customer id
   • firstname is the customer's first name
   • lastname is the customer's last name
2. products.csv keeps product info:
   • id is a numeric product id
   • name is the human-readable name
   • cost is the product cost in euros
3. orders.csv keeps order information:
   • id is a numeric order id
   • customer is the numeric id of the customer who created the order
   • products is a space-separated list of product ids ordered by the customer

Manually dealing with those files is hard and error-prone, and they've asked for your help writing some code to make their lives easier.

Task 1

Right now the orders.csv doesn't have total order cost information.

We need to use the data in these files to emit a order_prices.csv file with the following columns:

• id the numeric id of the order
• euros the total cost of the order

Task 2

The marketing department wants to know which customers are interested in each product; they've asked for a product_customers.csv file that, for each product, gives the list of customers who have purchased this product:

• id numeric product id
• customer_ids a space-separated list of customer ids of the customers who have purchased this product

Task 3

To evaluate our customers, we need a customer_ranking.csv containing the following columns, ranked in descending order by total_euros:

• id numeric id of the customer
• firstname customer first name
• lastname customer last name
• total_euros total euros this customer has spent on products