FAQ: Aggregates in R - Combining Grouping with Filter

This community-built FAQ covers the “Combining Grouping with Filter” exercise from the lesson “Aggregates in R”.

Paths and Courses
This exercise can be found in the following Codecademy content:

Learn R

FAQs on the exercise Combining Grouping with Filter

There are currently no frequently asked questions associated with this exercise – that’s where you come in! You can contribute to this section by offering your own questions, answers, or clarifications on this exercise. Ask or answer a question by clicking reply (reply) below.

If you’ve had an “aha” moment about the concepts, formatting, syntax, or anything else with this exercise, consider sharing those insights! Teaching others and answering their questions is one of the best ways to learn and stay sharp.

Join the Discussion. Help a fellow learner on their journey.

Ask or answer a question about this exercise by clicking reply (reply) below!
You can also find further discussion and get answers to your questions over in #get-help.

Agree with a comment or answer? Like (like) to up-vote the contribution!

Need broader help or resources? Head to #get-help and #community:tips-and-resources. If you are wanting feedback or inspiration for a project, check out #project.

Looking for motivation to keep learning? Join our wider discussions in #community

Learn more about how to use this guide.

Found a bug? Report it online, or post in #community:Codecademy-Bug-Reporting

Have a question about your account or billing? Reach out to our customer support team!

None of the above? Find out where to ask other questions here!

I know we are filtering based on a groups aggregate statistic, and returning only the values where that is true (so, only the groups where that is true). It makes sense to me that the actual aggregate that we use to filter does not affect the values in the data frame (it isn’t applied to them, only to select them).

However, can anyone help me understand why the groups we create with group_by() aren’t maintained, even after filtering?

Like, in this exercise we group the orders data frame by shoe_type, then filter out the groups that aren’t popular (under 16 sales total).

But, in our final table that we make, the data frame is no longer grouped by shoe_type. I can see that only the boots, sandals, and wedges are present (the popular groups), but I would have expected ALL the boots, then ALL the sandals, then ALL the wedges after the group_by command.

Am I misunderstanding something with group_by() and the “sub-categories” it creates?
Is this R being intelligent for us, knowing that we probably don’t want those groups?

I’m implementing this fine, but I’d appreciate any guidance you might have to assist my conception of this.