Those “other” apply functions…
So you know lapply, sapply, and apply...but...what about rapply, vapply, or eapply? These are generally a little less known as far as the apply family of functions in R go, so this post will explore how they work. rapply Let's start with rapply. This function has a couple of different purposes. One is to recursively apply a function to a list. We'll get to that in a moment. The other use of rapply is to a apply a function to only those elements in a list (or columns in a data frame) that belong to a specified class. For example, let's say we have a data frame with a mix of categorical and numeric variables, but we want to evaluate a function only on the numeric variables. Use rapply to…