Advanced Data Processing with Python and Polars

Level: Real-World

Project Description

In yesterday's project, we used Polars to process some invoice data. Today, we will use the same data, but perform more complex operations. We will calculate the total amount spent by each customer, their total number of purchases, and rank the customers by expenditure.

Before Coding

Download the CSV files in this link and place them in a folder named “invoices”. Place the “invoices” folder in the same directory with your Python script.

How the Project Works

(1) The program makes a list of all the CSV files located in the “invoices” directory and iterates over the files and loads each file as a Polars dataframe. (2) Then, the program calculates and prints out the total number of invoices (i.e., 24) and the total of the Price columns of all files (i.e., $5070.50). (3) Then, the program calculates the total sum spent by each customer in all files and ranks the customers by the amount they have spent. (4) The dataframe created in step 3 is exported to a CSV file and a message is printed out in the command line that the report was saved successfully.

Here is what the program should print out in the command line:

Prerequisites

Required Libraries: glob, polars
Installation: pip install polars
Required Files: Download the required files in the “Before Coding” section.
IDE: You can use any IDE on your computer to code the project.

Danger Zone

Here is the code solution: