Python Data Scripts

Python scripts built and deployed against live data for real business operations.

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Customer Loyalty Points Engine

Python · Pandas · Deployed at Discover Diving (2022)

Aggregates transaction data exported from a POS system, calculates spend-based loyalty points at 2.5% of net sales, and reconciles balances across the full customer database. Output is a cleaned CSV ready to import back into the POS.

What it does

• Ingests a receipts export and existing customer database as CSVs
• Deduplicates customers and aggregates total spend and visit count
• Calculates points balance at 2.5% of net sales per customer
• Reconciles against the existing customer file — updates known customers, zeros out anyone with no recent transactions
• Exports an updated customer CSV ready for POS import

Files

File	Description
customer_points_v1.py	Original deployed script (2022) — iterative approach
customer_points_v2.py	Refactored version — vectorised Pandas, typed functions, cleaner structure

Input format

receipts-YYYY-MM-DD-YYYY-MM-DD.csv

Column	Description
Customer name	Customer identifier
Net sales	Transaction value (£)

customers-YYYY-MM-DD.csv

Column	Description
Customer name	Customer identifier
Points balance	Current points balance to be updated

Output

customerUpdatedPoints.csv — full customer database with recalculated points balances.

Setup

pip install pandas
python customer_points_v2.py

Update the file paths in load_data() to match your CSV exports.

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Tech

• Python 3
• Pandas