Written By: @Ashley

Table of Contents

**The Basics Optionals Structs Closures Additional Resources**

The Basics

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To do the fun stuff, you always got to start with the basics! :)

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Data Types

Variables & Constants

Arrays

Control Statements

Loops

Functions

Optionals

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Optionals are a data type in Swift where a variable may or may not have a value. Any of the data types in the **Data Types** section can become an optional. Declaring an optional is done by including the data type name followed by a question mark ? just like in the code snippet below.

If an optional has no value, that means the optional is nil.

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var title: String = "Green Eggs and Ham"
var authorOfBook: String? = nil

Wait, but what’s the difference between String and String??