# Sets

Understand the data structure of sets, how to use them, and how they differ from lists.

## We'll cover the following

Sets are linear data structures very similar to lists. However, they do have a few notable differences.

## What is a Set? #

Just like a list, a set is a linear data structure that contains multiple elements. However, sets are different from lists because:

- Sets have no concept of ordering, meaning there is no such thing as “the third element” in a set.
- Sets cannot contain duplicates; you cannot have a set that, for instance, contains
`42`

twice.

Both these properties of sets have implications for programming with them that you should be aware of when using them.

## Creating a Set #

The way to create a set should look familiar to you:

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