Scala for the Impatient, 3rd Edition

Chapter 4. Maps, Options, and Tuples

Topics in This Chapter A1

• 4.1 Constructing a Map

• 4.2 Accessing Map Values

• 4.3 Updating Map Values

• 4.4 Iterating over Maps

• 4.5 Linked and Sorted Maps

• 4.6 Interoperating with Java

• 4.7 The Option Type

• 4.8 Tuples

• 4.9 Zipping

• Exercises

A classic programmer’s saying is, “If you can only have one data structure, make it a hash table.” Hash tables—or, more generally, maps—are among the most versatile data structures. As you will see in this chapter, Scala makes it particularly easy to use them.

When looking up a key in a map, there may not be a matching value. An option is perfect for describing that situation. An option is used in Scala whenever a value may be present or absent.

Maps are collections of key/value ...