Filling NaN Values in a DataFrame Based on Grouped Data Using Python Pandas

Resolving InvalidIndexError on Concat in Pandas: Strategies for Successful DataFrame Merging

How to Add Calculated Columns to Pandas DataFrames: A Comparison of Three Approaches

Joining DataFrames on Indices with Different Number of Levels in Pandas

Merging Dataframes with Common Values but No Common Columns Using Pandas Operations

Remove Duplicate Records in Pandas DataFrame Based on Alphabetical Order

Replacing Part of a String in a Column by Position Using Pandas in Python

Dropping Duplicate Rows and Combining Columns in Pandas DataFrame with Condition

Selecting Rows in a MultiIndex DataFrame by Index Without Losing Any Levels

Conditional Logic in R: Writing a Function to Evaluate Risk Descriptions