Filtering for states with a minority majority

Previously, we examined using Boolean arrays to filter rows. In a similar fashion, when using the .groupby method, we can filter out groups. The .filter method of the groupby object accepts a function that must return either True or False to indicate whether a group is kept.

This .filter method applied after a call to the .groupby method is completely different to the DataFrame .filter method covered in the Selecting columns with methods recipe from Chapter 2, Essential DataFrame Operations.

One thing to be aware of is that when the .filter method is applied, the result does not use the grouping columns as the index, but keeps the original index! The DataFrame .filter method filters columns, not values.

In this recipe, we use the college dataset to find all the states that have more non-white undergraduate students than white. This is a dataset from the US, where whites form the majority and therefore, we are looking for states...