Composite Data Types
Go offers support for maps and structures, which are composite data types and the main subject of this chapter. The reason that we present them separately from arrays and slices is that both maps and structures are more flexible and powerful than arrays and slices. The general idea is that if an array or a slice cannot do the job, you might need to look at maps. If a map cannot help you, then you should consider creating and using a structure.
You have already seen structures in Chapter 1, A Quick Introduction to Go, where we created the initial version of the phone book application. However, in this chapter we are going to learn more about structures as well as maps. This knowledge will allow us to read and save data ...