In today's insightful lesson, we will delve into a cornerstone of Ruby's data structure ecosystem, the Hash. Building upon our understanding of sets from previous lessons, this session introduces you to the Hash, a powerful structure that stores key-value pairs. This setup makes the Hash an ideal choice when swift data access through keys is necessary.
Hashes utilize the principle of hashing, which enables average constant time complexity for several core operations, thereby enhancing their efficiency. By the end of this lesson, you will have gained practical knowledge of creating, manipulating, and understanding the workings of Hashes, including their implementation and complexity in handling data.
Before we commence, let's formally define a Hash. A Hash in Ruby is a collection that stores key-value pairs, where each key is unique and efficiently manages these pairs. Hashes do not guarantee any specific order for the stored pairs; in other words, the order can change over time (although in modern Ruby versions, insertion order is maintained by default).
Hashes function using the principle of hashing. Here, a key is rendered to a hash code by a hash function, and this numeric code identifies the storage location for the key-value pair. Let's visualize a simple creation of a Hash:
