question 198 CSV JSON & JSONL · hard

A customer spend report from two CSV files

Marketing wants every customer with how many orders they received and how much they spent, biggest spenders first. Join the customers file with the orders file and write the report.

Functioncustomer_report(customers_path, orders_path, dest)

customersCSV customer_id,first_name,last_name,email,city,state

ordersCSV order_id,customer_id,status,total; only delivered orders count; orders from customers not in the customers file are ignored

Writesdest with header customer_id,name,orders,spent: name is "First Last", spent has two decimals; every customer appears, with 0 and 0.00 if they had no delivered orders

Orderby spent, highest first; equal amounts by customer_id ascending

Returnsthe number of customers written

Examples

callcustomer_report('customers.csv', 'orders.csv', '_q0.csv')returns4

callcustomer_report('one_customer.csv', 'orders.csv', '_q01.csv')returns1

callcustomer_report('no_customers.csv', 'orders.csv', '_q02.csv')returns0