Absolute Beginner's Guide to Algorithms: A Practical Introduction to Data Structures and Algorithms in JavaScript

11

Hashtable (aka Hashmap or Dictionary)

When it comes to data structures, the hashtable holds a special place in all of our hearts. It takes storing and retrieving values really quickly to a whole new level. For this reason, we’ll find hashtables used in the many, MANY situations where we need to cache data for quick access later. We’ll see hashtables used by other data structures and algorithms for their functioning. In this chapter, we go deep into what makes hashtables (often also referred to as hashmaps or dictionaries) really awesome.

Onward!

A Very Efficient Robot

Here is the setup that will help us explain how hashtables work. We have a bunch of food that we need to store (Figure 11-1).

FIGURE 11-1

Let’s talk about food!

We also ...