> For the complete documentation index, see [llms.txt](https://howtocode.trek.io/topics/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://howtocode.trek.io/topics/deep-dives/computer-science/data-structures.md).

# Data structures

## Introduction

In the previous section, we discussed `Big O` and `Algorithms`; two tools that you may want to use in your quest to write quality, performant code. In this section, we put that to the side and we look at `Data Structures`, what they are and how they can be useful.

## Prerequisites

If you're unsure of how to implement classes and objects in your chosen language, now is the time to brush up on that knowledge; because this section will be asking you to make use of it.

## What is a data structure?

A data structure is simply an object or collection of objects that is designed to enable you to store, access and manipulate the data within it in a certain way. This can help access and modifications easy, enable the use of certain algorithms to tackle a specific problem or restrict how we interact with our data into very specific methods. Ruby, JavaScript and various other languages have some data structures built-in for you to make use of; but we will soon look into how we could implement them as educational examples.

You will have certainly already dealt with one data structure already... `The Array`. `Arrays` can conceptually be thought of a line of boxes, and you can insert, look at, change and remove these boxes. In our next lesson, we'll be looking at data structures similar to arrays, but at the same time rather different.

## Assignment

Have a look back at previous code you have written outside of this course. Have there been other ways you've stored data other than simply arrays?


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://howtocode.trek.io/topics/deep-dives/computer-science/data-structures.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.