R has the appearance of a procedural programming language. However, it is built on another language, known as S programming language. S leans towards functional programming. It also has some object-oriented characteristics. This means that there are many complexities in the way that R works.
In this section, we will look at some of the fundamental building blocks that make up key control structures in R, and then we will move onto looping and vectorized operations.
R has five assignment operators, which are listed here:
<-
->
=
<<-
->>
In this book, we will use the following assignment operator:
<-
We will use this assignment operator here, because it is used commonly in examples on well-known internet sites such as StackOverflow (http://stackoverflow.com/). It's also possible to use the rightward assignment operator, but that is confusing for many people so it is not used here. Note also that the equals sign isn't used here...