Stop Using VLOOKUP: How I Automate 4 Hours of Excel Work in 4 Seconds with Python

We have all been there. It's Friday afternoon, and you have to generate the "Weekly Sales Report." This involves: ​Opening 5 different CSV files sent by 5 different regional managers. ​Copy-pasting them into one master sheet. ​Cleaning up the date formats because John in Sales sent his as DD-MM-YYYY but the system needs MM-DD-YYYY. ​Running a VLOOKUP against the "Product Master" sheet to get prices. ​Creating a Pivot Table. ​If you are lucky, this takes an hour. If you are unlucky, Excel crashes because you hit the 1,048,576 row limit. ​In 2026, manual spreadsheet wrangling is obsolete. Here is how I replaced this entire workflow with a Python script using Pandas. ​1. The Setup: Ingesting Data instantly ​Instead of opening files one by one, we use Python's glob library to find all files in a folder and read them into a Pandas DataFrame. import pandas as pd import glob Find all CSVs files = glob.glob("sales_data/*.csv") Read and combine them in one line df = pd.concat([pd.read_csv(f) fo