Here's an example code that demonstrates how to use the `groupby` and `agg` functions together:

Counting City Appearances in a Pandas DataFrame by Year: A Step-by-Step Guide

Merging Right Dataframe into Left Dataframe, Preferring Values from Right Dataframe and Keeping New Rows

Handling Character Encodings to Prevent UnicodeDecodeError in Python with Pandas

Transforming Values in a Pandas DataFrame: A Guide to Using np.where

Understanding Histograms in Pandas DataFrames with Python

Temporary DataFrames with Specific Cities

Understanding pytest.mark.parametrize: Testing Functions that Return Two Values

Replacing Values in a DataFrame Based on Conditions with Pandas

Transferring Multiple Columns into a Vector Column Using Pandas and Python: A Comparative Analysis of Two Approaches