# Sets

Understand the variations of sets in Python.

## We'll cover the following

This lesson lists different implementations of a set provided by Python 3 and explains when to use which built-in support.

## Introduction

A **set** is a collection of items that does not allow duplicates. It’s an *unordered* collection.

⚠️

Note:In case you forget, the expression of a set involves curly-braces`{}`

in Python. To create an empty set, we call the`set()`

function. Using`{}`

without any values in it will create adictionary, not aset.

## Types of sets

### Mutable set with `set`

The `set()`

creates a *mutable* structure. Operations like dynamic insertion and deletion are allowed. Python provides basic sets’ operations, like **intersection** and **union**.

Run the following program to have an overview.

Get hands-on with 1400+ tech skills courses.