R Tutorial: The Nine Systems

Want to learn more? Take the full course at https://learn.datacamp.com/courses/object-oriented-programming-with-s3-and-r6-in-r at your own pace. More than a video, you'll learn hands-on coding & quickly apply skills to your daily work. --- One quirk of R is that there are often half a dozen different packages that do more or less the same thing. This is mostly by design. R’s great strength is that anyone can create a package, submit it to CRAN (or one of the other package repositories) and share it with millions of other users. Unfortunately, it’s also easy to become overwhelmed by choice, and not know which package is best for you. In the case of object-oriented programming, there are nine different options, so let’s take a moment to work out which of these you might want to spend time learning. R5 and mutatr were both experimental systems that never made it into real-world use before being abandoned. It’s almost impossible to use these, even if you wanted to. OOP is defunct and no longer available. Cross that off your list. proto had a brief moment of popularity as the underlying system in early versions of the ggplot2 package but is no longer really used. Again, you shouldn’t consider this for your projects. R-dot-oo has been around for years, but hasn’t really taken off at all. Don’t bother with it. That’s great progress. Already we’ve narrowed down our list from nine to four. Let’s take a look at the others in a bit more depth. The S3 system was introduced in the third version of the S language that was the precursor to R. It’s been around since the 1980s, so it’s completely mature, and still in wide use. S3 is a very simple system. In fact it only implements one feature of object-oriented programming, that is, the ability to have functions work in different ways on different types of object. It’s a one-trick pony, but it’s a great trick. Using S3 is a fundamental R skill that you need to learn. S4 was introduced, as you might be able to guess, in