In this chapter, you learned about a number of built-in functions for manipulating character vectors and converting between date/time objects and their string representations. You also learned about the basic idea of regular expressions, a very powerful tool to check and filter string data and extract information from raw texts.

With the vocabulary we built in this and previous chapters, we are now able to work with basic data structures. In the next chapter, you will learn about some tools and techniques to work with data. We will get started with reading and writing simple data files, producing graphics of various types, applying basic statistical analysis and data-mining models on simple datasets, and using numeric methods to solve root-solving and optimization problems.