Numerical Computing with Python

How it works...

The syntax for the groupby method is not as straightforward as other methods. Let's intercept the chain of methods in step 2 by storing the result of the groupby method as its own variable

>>> grouped = flights.groupby('AIRLINE')>>> type(grouped)pandas.core.groupby.DataFrameGroupBy

A completely new intermediate object is first produced with its own distinct attributes and methods. No calculations take place at this stage. Pandas merely validates the grouping columns. This groupby object has an agg method to perform aggregations. One of the ways to use this method is to pass it a dictionary mapping the aggregating column to the aggregating function, as done in step 2.

There are several different flavors of syntax that produce ...