Here's a refactored version of the code with proper indentation, comments, and a clear structure:

Handling Multiple Iterations Over the Same Column in Pandas DataFrames Based on Criteria

Extracting Middle Values: A Deep Dive into GroupBy Operations with Pandas

Avoiding Gross For-Loops on Pandas DataFrames: A Guide to Vectorized Operations

Formatting Pandas DataFrames in Jupyter: Aligning Index and Columns Separately for Improved Readability and Analysis.

How to Merge Two Pandas Dataframes Based on Multiple Conditions While Ensuring Each User from the Database Can Only Be Used Once

Sampling a Pandas DataFrame Based on Priority Groups: A Comprehensive Guide

Converting Pandas DataFrames to Lists: A Comprehensive Guide

Creating a DataFrame from a Variable Length Text String in Python Using NLTK and Pandas

Optimizing Data Shifting in Pandas: A More Efficient Approach Using groupby.cumcount() and set_index()