Numerical Computing with Python

How it works...

It is common for the result of a groupby aggregation to produce a DataFrame or Series with multiple axis levels. The resulting DataFrame from the groupby operation in step 1 has multiple levels for each axis. The column levels are not named, which would require us to reference them only by their integer location. To greatly ease our ability to reference the column levels, we rename them with the rename_axis method.

The rename_axis method is a bit strange in that it can modify both the level names and the level values based on the type of the first argument passed to it. Passing it a list (or a scalar if there is only one level) changes the names of the levels. Passing it a dictionary or a function changes the values of the ...