Swift Closures Explained

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Before I start this video, I started searching for videos on closures , while actively using “100 days of SwiftUI” lesson plan, but during the first couple lessons involving closures, I could not get out of my head the question “If functions do everything closures do, why then do closures even exist?” So hopefully I get that answer from this video, because this thought it slowing down my ability to progress in learning swift.

I am a fan but I think Dr Angela Yu’s course explain it a little better this time.

Was confused AF going through swift tour, but this video really cleared everything up.. thanks!!

Hey, very interesting!
Just needed some advice on when should I use a function or computed property with closures?

Excellent content! This answered so many questions quickly and kindly 👏

Extremely useful video. I came here for closures and learnt so many things I was confused ab all in one go thanks

I should have known that I could trust another Sean to explain this well

As a flutter developer who is learning SwiftUI I must say that it is the most horrible syntax I have seen for such a simple mechanism known in many other languages ​​such as "Callbacks".

Looking for ways to identify closures when we see their address in memory graph during debugging.
So often they just show an address. Is it possible to make a trailing closure more recognizable in mem graph? Or to find a closure by address wile debugging? Or to print the address of a trailing closure?

Not a swift dev but some good information here that if you already know this it makes it connect from a different perspective. Great video

Hi Sean! I've been working on my programing career for about 2 months now. I'm doing the 100 days of swift with Paul Hudson. Even tho this is all still a bit blurry i do appreciate your content since its starting to clear a bit of the fog that i had. Just wanted to stop by and say thanks! You'll probably see me around a bit more ✌

The video is great! But his definition of a a closure isn't correct. He says that closures are functions that can be passed around. But all functions can be passed around. The real difference between a closure and a function is that a closure has access to variables in the parent scope without needing to pass them in as arguments. This is a Square-Rectangle relationship. All closures are functions but not all functions are closures. What this video shows is that Swift has a short syntax for defining closures that makes them easy to use functions. But the shorthand syntax isn't what makes it a closure. Non-closure functions don't have access to variables in the parent scope unless you pass them in as arguments. Closures can just access variables in the parent scope without having to pass them in as arguments. The examples in this video are good for creating functions with a shorthand syntax that match the function signature but the examples in this video aren't unique to closures.

In Swift all functions are closures. If you define a function (not with closure syntax) in Swift inside of a scope it will have access to variables in the parent scope. This makes it a closure. But this isn't true in all languages and is an implementation detail of the language.

best teacher i found about swift fundamentals

Finally my Javascript knowledge helps me out. I picked these up quickly.

Excellent explanation, thank you so Much Sean

my issue with this video is it isn’t a discussion of closures in swift but a discussion of a syntactic sugar for function pointers.

unless i missed something, there wasn’t any point where you “closed over” or captured the environment when creating the closure, which is an essential part of closures. i assume you can also do this in swift closures but it wasn’t shown here

I absolutely loved the Swift Closures Explained video by Sean Allen. As someone who has struggled to understand closures, this video was a godsend. Sean does an amazing job of breaking down the confusing aspects of closures, like what the parenthesis mean and the shorthand syntax. He explains everything in a clear and concise manner, making it easy for even a beginner like myself to follow along.

I also appreciate the fact that Sean provides a promo code for Squarespace at the beginning of the video. It’s always great to get a discount when you’re starting a new website or domain.

Overall, I highly recommend this video to anyone who is struggling to understand closures, or anyone who wants to brush up on their Swift knowledge. Thank you, Sean, for creating such an informative and helpful video.

I've just started delving into the mystery that is closures. Your video helped both for what they are and, especially, why I will need to know them. Thanks!

awesome

A Question, is the var topStudentFilter always recalculated when 1. Its called, or 2.when the student array is changed, or3. at both times.

WOW! The most Clear and concise explanation I've seen on closures in 6years of developing.

I’m on my phone so not sure if this has been said before but it took me a while to figure out how to sort on multiple values….

Tuples!!!!

{ ($0.score, $0.name) > ($1.score, $1.name) }

This will sort first by descending score, then by descending name.

To sort by DESC score and ASC name:

{ ($0.score, $1.name) > ($1.score, $0.name) }

Wow, Sean. You are a very good teacher. Thank you for this. 👍🏼

Most easiest concept in swift is closure

Hi Sean are closures like object in java where you can call them whenever you need them

What a wonderful tutorial, clear but also full of knowledge. You really helped me understand the book of swiftUI, thanks a lot !

Excellent examples! Now do the same example with Async Await

Can I see a closure as an interface like in Java

slow down plz

Hey Sean, thanks for this. Can you make a video about Callbacks? Differences between completion handlers and Callbacks?

Thanks for the great videos, closures have been a source of mystery for me since I started. One question, in the first example, is the closure being passed in as a type for topStudentFilter?

“@escaping ? …. Who are we running from?” 😂

Sean you are without a doubt my number 1 iOS teacher. Thank you.

Well done, great explanations 👍

Thank you so much for clearly explaining the $0 and $1 in closures. I have read and studied it so many times but now I just got it in 1 minute.

Thank you!

Should I invest my time in Swift UI or UIkit? I'm an experienced Android developer and just starting to learning iOS development to boost my portfolio; not necessarily trying to get a job as an iOS dev at least for the next 1 - 2 years

Code magician, expecting more :) with closure and SwiftUI

I’m going to be honest with you, this was a G-R-E-A-T explanation. I’ve read so many Medium posts and Stack Overflow answers where people either try to sound too smart or they just don’t realize that they’re not speaking in layman’s terms (they’re speaking to other people who don’t need it explained). This took a very simple approach to something complicated and made it simple. FANTASTIC explanation!!! You do a great job of keeping things simple! Seriously. And I like your graphics!

Super understandable! Thank you for this video, finally i've got it 🤝

very good video!

Thanks!

I love this!

So now think of escaping as you’re putting popcorn in the microwave. But it’s taking so long to pop, you ask that one friend who’s in the kitchen to wait for it to finish popping and bring it back to the living room?

"empty parentheses and Void are the same thing" - man oh man, this is the kind of stuff that takes hours off the head banging waste of time trying to learn

Awesome video, Sean! Thank you for all the work you do!