# Data Structures

[Variables](https://icheka-ozuru.gitbook.io/sonarlang/syntax-basics/variables) explained what variables are (temporary location for storing data) and how to create and use them in **Sonar**.

The one downside to variables is that they can only store a single value of a single data type. Most of the time, this won't be a problem, but when you write programs that need to store and manipulate collections of data (such as an attendance register for a classroom), you'll need a way to store *collections of data*, instead of just single values.

**Sonar** offers two kinds of *collections: arrays and maps*.The following sections will explain how they can be used to create complex programs.