We are continuing our post series on S3 object orientation and interoperability in R. We have previously discussed what makes a good S3 class and how to choose a good parent for it, as well as when to write or not write a custom method. We have highlighted in particular how classes inheriting from data.frames can simplify user experience because of familiarity, and reduce developer workload due to the pre-existing S3 methods.

I have recently published a series of blog posts on the reasons why one may want to start using object-oriented programming (and more specifically R S3 classes) to improve interoperability with other tools from the ecosystem. But there are still questions I have not addressed directly, even if they may have been implicitly included sometimes: what makes a good object class? What good practices in class &