Advanced R

14

Expressions

In Chapter 13, you learned the basics of accessing and evaluating the expressions underlying computation in R. In this chapter, you’ll learn how to manipulate these expressions with code. You’re going to learn how to metaprogram: how to create programs with other programs!

Outline

• Section 14.1 begins with a deep dive into the structure of expressions. You’ll learn about the four components of an expression: constants, names, calls, and pairlists.
• Section 14.2 goes into further details about names.
• Section 14.3 gives more details about calls.
• Section 14.4 takes a minor detour to discuss some common uses of calls in base R.
• Section 14.5 completes the discussion of the four major components of an expression, and shows how you can ...