7. Dictionaries and Hashes | Learning JavaScript Data Structures and Algorithms

The hash table

In this section, you will learn about the HashTable class, also known as HashMap, a hash implementation of the Dictionary class.

Hashing consists of finding a value in a data structure in the shortest time possible. You have learned from previous chapters that if we would like to get a value from it (using a get method), we need to iterate through the structure until we find it. When we use a hash function, we already know which position the value is in, so we can simply retrieve it. A hash function is a function that given a key, and will return an address in the table where the value is.

For example, let's continue using the e-mail address book we used in the previous section. The hash function we will use is the most common one, called a "lose lose" hash function, where we simply sum up the ASCII values of each character of the key length.

Creating a hash table

We will use an array to represent our data structure to have a data structure very similar to the one we used in...

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Learning JavaScript Data Structures and Algorithms

By : Loiane Avancini

Learning JavaScript Data Structures and Algorithms

By: Loiane Avancini

Overview of this book

The hash table

Creating a hash table

Learning JavaScript Data Structures and Algorithms

By : Loiane Avancini

Learning JavaScript Data Structures and Algorithms

By: Loiane Avancini

Overview of this book

The hash table

Creating a hash table

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