Pandas Workout

6 Grouping, joining, and sorting

So far, we have looked at how to create data frames, read data into them, clean the data, and then analyze that clean, imported data in a number of ways. But analysis sometimes requires more than just the basics: we often need to break our input data apart, zoom in on particularly interesting subsets, combine data from different sources, transform the data into a new format or value, and then sort it according to a variety of criteria. This type of action is known in the pandas world as split-apply-combine, and it is our focus in this chapter. If you have experience with SQL and relational databases, you’ll find many similarities, in both principle and name, to functionality in pandas.

For example, a company ...