Grouping Data in Pandas

From Practical Business Pandas:

Comprehensive Guide to Grouping and Aggregating with Pandas

…This article will quickly summarize the basic pandas aggregation functions and show examples of more complex custom aggregations. Whether you are a new or more experienced pandas user, I think you will learn a few things from this article.

Practical Business Pandas has such a trove of good information. I partly blame this site for jump starting my interest in learning Python.