Swift Optionals and `nil`

⭐️ 👀 2023 WEB DEVELOPMENT BOOTCAMP starting in days! Join the waiting list to reserve your spot in my 10-weeks cohort course and learn the fundamentals, HTML, CSS, JS, Tailwind, React, Next.js and much much more! 👀 ⭐️

This tutorial belongs to the Swift series

Optionals are one key feature of Swift.

When you don’t know if a value will be present or absent, you declare the type as an optional.

The optional wraps another value, with its own type. Or maybe not.

We declare an optional adding a question mark after its type, like this:

var value: Int? = 10

Now value is not an Int value. It’s an optional wrapping an Int value.

To find out if the optional wraps a value, you must unwrap it.

We do so using an exclamation mark:

var value: Int? = 10
print(value!) //10

Swift methods often return an optional. For example the Int type initializer accepts a string, and returns an Int optional:

This is because it does not know if the string can be converted to a number.

If the optional does not contain a value, it evaluates as nil, and you cannot unwrap it:

nil is a special value that cannot be assigned to a variable. Only to an optional:

You typically use if statements to unwrap values in your code, like this:

var value: Int? = 2

if let age = value {

One more thing! ⚠️ ✋

At the end of January I will organize the Web Development Bootcamp.

It's a 10-weeks long cohort online course where I will guide you to becoming a Web Developer.

It's not "just a course". It's a big event I organize once a year.

We'll start from zero, learn the fundamentals of Web Development, HTML CSS, JavaScript, Tailwind, Git, using the command line, VS Code, GitHub, Node.js, we'll then learn React, JSX, how to use PostgreSQL, Astro, Next.js, Prisma, deploying on Netlify/DigitalOcean/Fly/Vercel and much more! 

At the end of the first 10 weeks you'll know how to create web sites and web applications and I'll unlock you the 2nd phase of the Bootcamp: you will get access to a large number of projects exclusive to the Bootcamp graduates, so you can follow my instructions to build things like private areas with authentication, clones of popular sites like Twitter YouTube Reddit, create e-commerce sites, and much much more.

Because once you got the fundamentals, you only learn by working on real, exciting projects.

To find out more, visit bootcamp.dev