100daysofswiftui on dev.endevour

FriendFace 61 Feedback

Sat, 26 Nov 2022 00:00:00 +0000

As usual after a challenge, I compare my efforts to Paul’s model solution. Just to quickly recap the app, it sucks up some data (Users who have multiple friends) and displays it. The change in this challenge was to convert it to add that data to a Core Data store so that if a future network error prevented accessing new data, it could still display the old.

Merge Policy

The first difference is that Paul adds a merge policy. A Merge policy tells Core how to deal with any constraints defined in the data model. In this app, I’d defined the CachedUser.id as a constraint. The purpose of this is that under normal conditions the app would be picking up mostly the same data each time it started up. We don’t want scabs of duplicate data, so constraining users based on their unique id is smart.

61 Done

Fri, 25 Nov 2022 00:00:00 +0000

I think I’ve finally completed the minimum work for Day 61 of #100DaysOfSwiftUI . The task was to suck up some data in JSON, decode it. back it up into a Core Data graph then display the data from the Core Data.

I got stuck on dealing with the one:many relationship and had to revisit that from a different source to get my head around it, after that it was straightforward. Other small problem I ran into was that I created the id in the CachedUser as a UUID from (newly formed) habit. Then when I went to copy it in from the JSON version, it wouldn’t let me. When I realised my mistake and changed it in the data model, I still could not figure out why it wasn’t working - but of course I hadn’t regenerated the code for the ManagedObject. I just had to change the property type in the already generated code from UUID to string and I was back in business.

FriendFace Feedback

Tue, 15 Nov 2022 00:00:00 +0000

After each app, I use my HackingWithSwift+ membership to view Paul’s version of the app as a way to judge my performance. Yesterday’s app was “FriendFace ” - download some JSON of a number of people (including their friends) and display it.

UUID

In my struct, I’d just specified the User.id as a string, Paul uses UUID - this makes no difference to the app as it stands, but is much better if we ever needed to add users.

FriendFace

Mon, 14 Nov 2022 00:00:00 +0000

The Day 60 Milestone is a demo app that vacuums up some JSON and displays it in a list in a NavigationView that links to a details page. Nothing super strenuous, the steps were something like this:

Download the JSON and have a look at the structure. Firefox has a simple JSON viewer built in, so it was straightforward to see this is an array of users, which along with some (mostly string) properties contains an array of tag strings, and another array of friends.

Project 12 Feedback

Fri, 11 Nov 2022 00:00:00 +0000

As usual, I watch Paul’s solution video, and compare it to mine.

Task 1

This was passing in the predicate as a String. I passed the whole thing, but as I figured out along the way, Paul meant just the operator word. He also added some buttons to test it better, which I didn’t think of till Task 3 - it would have saved me some simulator runs.

Project 12 Challenges

Thu, 10 Nov 2022 00:00:00 +0000

Project 12 was a series of code tutorials around developing CoreData concepts rather than a real app, but the challenges are based on a very small app that uses a subview to allow dynamic (ie changeable at runtime) filtering of a list of data. The reason this would be tricky is that the @FetchRequest is a property of a view - and therefore mutable. The trick is to have a subview to build that part of the view, and to pass parameters into it which build the fetchrequest using an underscore.

You Can Take Big Steps When You Feel Safe

Wed, 09 Nov 2022 00:00:00 +0000

Day 58 of #100Days feels like complex topics are being dropped in pretty fast. We tackle one:many data relationships and how to set them up in CoreData, using CoreData constraints and setting a merge policy to manage conflicts, and even the underscore to access the actual property inside a wrapped property struct (needed for dynamic filtering in a view).

I’ve mentioned before that I think Paul Hudson is an excellent teacher, and an example of this is that even though this was a day with a lot of challenging material, I’m not worried. I followed the discussion and tried the code, and more importantly I’m anticipating these new skills will be practiced in the next app, and probably shortly after I’ll be writing an app using them.

Bookworm Feedback

Mon, 07 Nov 2022 00:00:00 +0000

I did so well on this one that it’s not going to make a very interesting post. My first two challenge solutions were pretty much character for character the same - so not much to report.

On the third challenge, there was a minor difference in the display process. I had done this:

let date = book.date ?? Date()
Text(date.formatted(.dateTime.day().month().year()))
 .foregroundColor(.secondary)
 .opacity(date == book.date ? 1 : 0)

But @twostraws went:

Bookworm Challenges

Sun, 06 Nov 2022 00:00:00 +0000

Another set of challenges for a #100DaysofSwiftUI tutorial app. Project 11 was a book tracking app - the big new thing was using CoreData. Here’s the challenges for it .

Right now it’s possible to select no title, author, or genre for books, which causes a problem for the detail view. Please fix this, either by forcing defaults, validating the form, or showing a default picture for unknown genres – you can choose.

CoreData and the Preview

Fri, 04 Nov 2022 00:00:00 +0000

I’ve noticed Paul is inclined to ignore the preview and run his code in the simulator to check its operation. That’s valid, but it seems quicker, and reassuring, to see it in the preview as I type.

This led to a small problem with Day 53 that uses CoreData. When I added a student in the preview, it looked like this, and was immediately followed with a crash report.

Cupcake Corner Feedback

Thu, 03 Nov 2022 00:00:00 +0000

As usual, here’s my thoughts comparing my attempts at the challenges to Paul’s. Usually he’s better!

1) Whitespace

The task was to validate the order address properties, not just by checking they are not empty, but also that they don’t just contain spaces. I went the bruteforce route since there was no .isEmptyIncludingWhitespace method.

var hasValidAddress: Bool {
 let trimmedName = name.trimmingCharacters(in: .whitespacesAndNewlines)
 let trimmedStreetAddress = streetAddress.trimmingCharacters(in: .whitespacesAndNewlines)
 let trimmedCity = city.trimmingCharacters(in: .whitespacesAndNewlines)
 let trimmedZip = zip.trimmingCharacters(in: .whitespacesAndNewlines)

 if trimmedName.isEmpty || trimmedStreetAddress.isEmpty || trimmedCity.isEmpty || trimmedZip.isEmpty {
 return false
 }
 return true
}

As soon as Paul mentioned extending String, I facepalmed - of course, just create the method I want on string. Paul’s is a one line extension - neater, and Swiftyier.

Cupcake Corner challenges

Wed, 02 Nov 2022 00:00:00 +0000

Day 52 of #100Days was the challenges to the Cupcake Corner app - an app that allows you to build a one-row order, encode it as JSON and submit it to an API with a URLSession. To allow the order to be passed around, it’s an @ObservedObject which meant that a few extra hoops needed to be jumped through to make it Codable.

1) Whitespace validation

The tutorial app validates the order address by checking that each field is not empty, but it can be fooled by just entering some spaces. The first challenge was to fix that.

Top Four Reasons why @TwoStraws is a Good Teacher

Tue, 01 Nov 2022 00:00:00 +0000

Good Questions

At various points in the 100 Days of SwiftUI course, you get asked sets of questions to check you’ve understood the preceding material. They’re usually presented as two different statements, one of which is true, and the other false. It’s actually a really good technique - the student feels like they’ve got a couple of opportunities to figure it out, plus they are forced to read both statements and think about them. Paul does a similar thing in the Unwrapped app - there, the questions are often presented as “Is this valid Swift code” and the user needs to scan through it all looking for mistakes. It’s checking your understanding, and making you a thoughtful debugger!

Day 47 - Habits App

Thu, 27 Oct 2022 00:00:00 +0000

I’ve been mucking around with the Habits app too long - it’s started to look like procrastination. It already meets the specification , so I’m calling it an MVP and moving on.

This is the first app of mine I’ve loaded onto my phone and started using, and there are a couple of things I’d like to do with it. It currently just lets you specify how many days between an activity repeating - so if you say you should go to the gym every second day, and you complete that activity on Monday, “Gym” will make it’s way to the top of the list on Wednesday. While it’s waiting in the list for Wednesday to come around, it will show the “Due” time as being exactly 48 hours after you last pressed “done” on it. But if the habit you want is to go to the gym after work at 6:00pm that’s when you want it to be due. I’d like that.

Drawing Feedback

Wed, 19 Oct 2022 00:00:00 +0000

Here’s the summary of my learning from comparing my efforts with Paul’s solutions to the Project Nine challenges from Day 46 of his 100 Days of SwiftUI course .

Create an Arrow shape – having it point straight up is fine. This could be a rectangle/triangle-style arrow, or perhaps three lines, or maybe something else depending on what kind of arrow you want to draw.

Project 9 - Drawing

Tue, 18 Oct 2022 00:00:00 +0000

These few days of #100DaysOfSwiftUI we made some pretty shapes by playing around with some of the SwiftUI systems for drawing on the screen, including paths, shapes, transformations, ImagePaint, drawingGroup() to use Metal rendering, blurs, blend modes and using animatableData for animating - which I think is the solution to an animation problem in my TimesTable app I hadn’t been able to solve yet.

Moonshot Feedback

Sat, 15 Oct 2022 00:00:00 +0000

I’ve watched Paul’s solution to the Moonshot challenges (the solutions are one of the perks of being a Hacking With Swift subscriber). When I’m solo learning like this its one of the few ways I can get any feedback on my coding, so I highly value it, and usually write one of these posts as a way to ensure I reflect on it.

Moonshot Challenges

Fri, 14 Oct 2022 00:00:00 +0000

Another few coding challenges at the end of a tutorial app in the 100 Days of SwiftUI course. The app is a sort of information app - composed of navigation views going down into more detail about the Apollo space missions. The most exciting revelation for me was how straightforward it is to pull JSON into your apps data structures.

Challenge 1

Add the launch date to MissionView, below the mission badge. You might choose to format this differently given that more space is available, but it’s down to you.

iExpense Feedback

Wed, 12 Oct 2022 00:00:00 +0000

I finally got around to looking at Paul’s solutions for the iExpense challenges .

Use the user’s preferred currency, rather than always using US dollars.

Same approach as me,

.currency(code: Locale.current.currency?.identifier ?? "USD")

except that he does the work in a local variable which is a bit neater. Since it appears in two places - the display view and the view for adding an expense, this would mean duplicating it, making it global (not rare for user default type settings) or passing it down through the view hierarchy. I feel either of the first two options are fine for this project, but Paul is thorough and extends the FormatStyle protocol, only for currency, to have a new computed property .localcurrency - which is a great solution.

iExpense Challenges

Sun, 02 Oct 2022 00:00:00 +0000

Day 38 is three challenges on the iExpense app - a simple expense tracking app that uses UseDefaults for storing it’s data.

Locale

Use the user’s preferred currency, rather than always using US dollars.

One of the joys of modern programming (as opposed to mid-1990’s programming) is the ability of the internet to give you answers. I knew the answer to this would be lurking in the locale environment variable, but instead of looking it up , just googled, and found a viable looking solution on Reddit .

Times Tables -Day 35 Challenge

Sat, 01 Oct 2022 00:00:00 +0000

The challenge for Day 35 of 100 Days of Swift UI was to create a simple times tables drilling app. I’ve met all the requirements, so I’ll move on, but I am struck by how ugly it is. Making better looking apps needs to be added to my goals. Especially since this app is intended to appeal to children, and is at the end of a few lessons on animation, this is definitely a weakness of mine at the moment.

User Defaults & Horizontal Pickers

Wed, 28 Sep 2022 00:00:00 +0000

I’m on the challenges for Day 35 of 100 Days of SwiftUI , and despite Paul’s very clear warning:

Important: It’s really easy to get sucked into these challenges and spend hours…

I have spent ages fiddling around, but of course still learning. My issue is not so much getting stuck on bugs, rather I keep wanting to do things I don’t know how to do.

One issue was solved for my by the wonderful Fireside Swift podcast. I’m working through the old (Steve & Zac) episodes, and they did one on the UserDefaults just when I wanted to be able to persist the multiplication table selection the user had made (this challenge app is a multiplication tables drill app for kids).

Ranges

Sun, 25 Sep 2022 00:00:00 +0000

I wondered aloud, in a previous post , about the differences in writing a range as

 ForEach(1..<21) {
 Text(String($0))
 }

versus

 ForEach(1...20) {
 Text(String($0))
 }

And that’s been answered in in one of the Day 34 articles. It sounds like older versions of Swift might not have allowed the second version.

Animating Guess The Flag

Sat, 24 Sep 2022 00:00:00 +0000

The challenges for Project 6 of 100 Days of SwiftUI was to add some animations to the Guess the Flag app from a little while ago. The animations themselves were not particularly tricky, my main issue was that I was creating the views for the three flags in a ForEach, so the animations were applied to all three flags, but we wanted different animations for the flag the user had clicked versus those they had not.

Animation Feedback

Sat, 24 Sep 2022 00:00:00 +0000

I had a look at Paul’s version of the challenge to animate the Guess The Flags app, and like me he’d hit on altering the amount of each animation depending on if it was the clicked on flag, but he’d done it with a lot less code - using the ternary operator in each of the modifiers - versus my approach of filling in an Int array for each of the effects and altering them depending on the user selection.

Project 5 - Word Scramble

Mon, 19 Sep 2022 00:00:00 +0000

Another 100 Days of Swift UI project wrapped up - this time a scrabble like word game. New techniques included saving a large text file in the app bundle and loading it (via a string) into an array on launch of the view. Also a short adventure into UIKit to use a UITextChecker.

Source .

Word Scramble Feedback

Mon, 19 Sep 2022 00:00:00 +0000

As is my practice now, after completing the challenges for Project 5 , I reviewed Paul’s solution (which is only available to subscribers) to see what he’d done better so I could learn from it.

Most of the differences where not of much significance, but there was a couple of things I picked up:

When the user had pressed the reset button, to empty the array of word guesses from the previous turn, I had

Project 4 Challenges

Fri, 16 Sep 2022 00:00:00 +0000

I’ve completed the Project 4 challenges (source) of the 100 Days of SwiftUI, no biggie - the increase in difficulty between each step of Paul’s bootcamp is small enough that it’s never too stressful, but large enough you feel like you’re progressing all the time.

Since I’ve paid to be a member of Hacking with Swift, one of the perks is to see Paul’s video solutions. I’ve not worries about it before, but I should - looking at them and comparing to my efforts is probably good feedback. So here’s the differences in our answers to the challenges.

Machine Learning

Thu, 15 Sep 2022 00:00:00 +0000

A few years ago when I still used a Tom-Tom for car navigation, I was a little freaked out when it started offering suggestions on where to go to when I started the car - guessing, usually correctly, where I wanted to go. Like - how did it know I was leaving school for band practice two towns over?

Clearly, is must have been collecting data on times/days and departure locations to learn some of my habits. It felt quite invasive, but I thought it must have been on-device since I had the wifi turned off in the unit.

Rock, Paper Scissors (2)

Tue, 13 Sep 2022 00:00:00 +0000

When I was forced by a deadline into delivering this project, I noted in its post that there was a number of improvements to make:

The rock paper scissors could be some better data structure than an array and some ints.

I don’t love the try to win, try to lose aspect, but the client specified it

Having the didUserWin and didComputerWin funcs is a cop out – that should probably be a single function returning a win/lose/draw type

I also am unhappy with nesting them in the view namespace to use my #consts

duplicating the last part of the view but making the elements .hidden() to keep the same spacing seems like a kludge

when I added the link to the Hacking With SwiftUI page with the app brief just now, I noticed I haven’t done the scoring the way it was asked for

Here’s the progress

Rock, Paper, Scissors (1)

Sat, 10 Sep 2022 00:00:00 +0000

As I mentioned yesterday, I needed to make some progress to blog about, and I had a half working version of a Rock, Paper, Scissors for Day 25 so I pushed myself to get that working.

There’s lots in the code below I don’t love.

The rock paper scissors could be some better data structure than an array and some ints.
I don’t love the try to win, try to lose aspect, but the client specified it
Having the didUserWin and didComputerWin funcs is a cop out - that should probably be a single function returning a win/lose/draw type
I also am unhappy with nesting them in the view namespace to use my #consts
duplicating the last part of the view but making the elements .hidden() to keep the same spacing seems like a kludge
when I added the link to the Hacking With SwiftUI page with the app brief just now, I noticed I haven’t done the scoring the way it was asked for

source on github

.self in ForEach

Wed, 07 Sep 2022 00:00:00 +0000

I’m on Day 25 of Hacking With SwiftUI, and Paul is making a point about how SwiftUI can loop over an array to build a view. He starts with this:

let agents = ["Cyril", "Lana", "Pam", "Sterling"]
VStack {
 ForEach(0..<agents.count) {
 Text(agents[$0])
 }
}

But then proposes an alternative:

let agents = ["Cyril", "Lana", "Pam", "Sterling"]
VStack {
 ForEach(agents, id: \.self) {
 Text($0)
 }
}

He explains the use of \.self here by saying

Project 3

Mon, 05 Sep 2022 00:00:00 +0000

This one’s not really a project, just a couple of little updates to earlier work, and a code snippet.

Challenge 1

Go back to project 1 and use a conditional modifier to change the total amount text view to red if the user selects a 0% tip.

The first one is pretty simple - a ternary condition to make the total red if the tip is set to zero.

Day 23 - Views and Modifiers - Part 4

Sat, 03 Sep 2022 00:00:00 +0000

Then the last trick for for decomposing the views, is to remember we can pass values when we init a struct. So something like this:

struct ContentView: View {

var body: some View {
 VStack{
 GreenPaddedText(text: "Hello")
 GreenPaddedText(text: "world")
 }
}


struct GreenPaddedText: View {
 var text: String

 var body: some View {
 Text(text)
 .foregroundColor(.green)
 .padding()
 }
}

}

Day 23 - Views and Modifiers - Part 3

Fri, 02 Sep 2022 00:00:00 +0000

The next part of day 23 started to make my brain hurt a bit. It’s easy to imagine that when presenting a complex screen - perhaps some data from a source as a mixture of images and text loaded from a database into a scroll-able view, that the view may start to get complex. Then it becomes good practice to decompose the views to make the code clearer, less error prone, and to avoid any unnecessary repetition.

Day 23 - Views and Modifiers - Part 2

Thu, 01 Sep 2022 00:00:00 +0000

Although “immutable” the view structs can contain some control statements such as if/then and for loops. So this is quite legal, and useful.

struct ContentView: View { @State private var likesGreen = true

var body: some View {
 if likesGreen {
 Text("Hello World")
 .background(.green)
 }
 else
 {
 Text("Hello World")
 .background(.blue)
 }
}

}

But Paul cautions against this, saying:

You can often use regular if conditions to return different views based on some state, but this actually creates more work for SwiftUI – rather than seeing one Button being used with different colors, it now sees two different Button views, and when we flip the Boolean condition it will destroy one to create the other rather than just recolor what it has.

Day 23 - Views and Modifiers - Part 1

Wed, 31 Aug 2022 00:00:00 +0000

I found this one of the trickier days, so I’ll write it out to clear up my thinking.

To draw to to screen in SwiftUI, we don’t call a command to draw on a canvas or window. Rather, a view is defined as an immutable struct of type some View. Here’s the simple one from the default Xcode project.

struct ContentView: View { var body: some View { Text(“Hello, world!”) .padding() } }

Project 2 - Guess the Flag

Wed, 31 Aug 2022 00:00:00 +0000

Another 100 Days project - the second tutorial one. This was once again a “V” design pattern (put everything in the view) and as I kept growing it, especially in the challenges, I had a growing sense of unease.

New things for me was how image assets work - identifying them with strings is convenient, but I’m hoping there’s safer system later using enums or something to avoid runtime surprises. Also the alert dialog box system. I was wondering how this was going to work in a declarative framework. I do not really approve of modal dialogs in mobile UI’s but I guess they have their place. I appreciated the gradients and frosted glass effects -super simple to implement, and if done thoughtfully, pretty.

Challenge 1

Mon, 29 Aug 2022 00:00:00 +0000

I’m up to Challenge 1 of 100 Days of SwiftUI (Day 19 ) which is to make your own simple (no MVVM) version of the app built in the previous three days. It’s about as simple as can be whilst still feeling like a real app. Something I hadn’t done before was limiting the keyboard to numbers or adding a toolbar to close it, so that was nice.

Something that’s not nice, is that when you touch into the text field to change the number, it’s not selected ready to type over (the way they always are in browser url fields) so you need to backspace over the previous entry. That’s the sort of anoying behaviour I don’t like. It seems (after some googling) there’s no straightforward way of addressing this in SwiftUI, with the best solution involving importing a package. I will come back to that because it is bugging me.

$==Commitment

Sun, 28 Aug 2022 00:00:00 +0000

Paul Hudson’s 100 Days of Swift UI course is free - the videos are on YouTube, all the reading and tasks are available on his website for free. Although I assumed he made his living from the prodigious number of Swift books he’s written, he doesn’t push them in the course (except for his free book Swift UI by Example ).

He’s so unpushy, I didn’t realise till a few days ago that you could pay to become a “subscriber” to Hacking with Swift . Really, he’s too nice.

Checkpoint 9

Sat, 20 Aug 2022 00:00:00 +0000

/* Your challenge is this: write a function that accepts an optional array of integers, and returns one randomly. If the array is missing or empty, return a random number in the range 1 through 100.

If that sounds easy, it’s because I haven’t explained the catch yet: I want you to write your function in a single line of code. No, that doesn’t mean you should just write lots of code then remove all the line breaks – you should be able to write this whole thing in one line of code.

Checkpoint 8

Wed, 17 Aug 2022 00:00:00 +0000

/* Your challenge is this: make a protocol that describes a building, adding various properties and methods, then create two structs, House and Office, that conform to it.

Your protocol should require the following: A property storing how many rooms it has. A property storing the cost as an integer (e.g. 500,000 for a building costing $500,000.) A property storing the name of the estate agent responsible for selling the building. A method for printing the sales summary of the building, describing what it is along with its other properties.

Checkpoint 7

Mon, 15 Aug 2022 00:00:00 +0000

/* Your challenge is this: make a class hierarchy for animals, starting with Animal at the top, then Dog and Cat as subclasses, then Corgi and Poodle as subclasses of Dog, and Persian and Lion as subclasses of Cat.

But there’s more: The Animal class should have a legs integer property that tracks how many legs the animal has. The Dog class should have a speak() method that prints a generic dog barking string, but each of the subclasses should print something slightly different. The Cat class should have a matching speak() method, again with each subclass printing something different. The Cat class should have an isTame Boolean property, provided using an initializer.

Checkpoint 6

Sat, 23 Jul 2022 00:00:00 +0000

/*
create a struct to store information about a car, including its model, number of seats, and current gear, then add a method to change gears up or down. Have a think about variables and access control: what data should be a variable rather than a constant, and what data should be exposed publicly? Should the gear-changing method validate its input somehow?
*/

struct Car {
 static let maxGear = 10
 static let minGear = 1
 var model = "no model"
 var seats = 4
 private (set) var currentGear = Car.minGear
 
 init (model: String, seats: Int) {
 self.model = model
 self.seats = seats
 }
 
 mutating func gearUp() {
 if currentGear < Car.maxGear{
 currentGear += 1
 }
 }
 
 mutating func gearDown() {
 if currentGear > Car.minGear{
 currentGear -= 1
 }
 }
 
}

var myUte = Car(model: "Rodeo", seats:2)
print("My \(myUte.model) has \(myUte.seats) seats and is in gear: \(myUte.currentGear)")
myUte.gearDown()
print("My \(myUte.model) has \(myUte.seats) seats and is in gear: \(myUte.currentGear)")
myUte.gearUp()
print("My \(myUte.model) has \(myUte.seats) seats and is in gear: \(myUte.currentGear)")

struct

Mon, 18 Jul 2022 00:00:00 +0000

Started on Day 10 of 100 days of etc etc today which is about structs. It was immediately clear when I first started looking at Swift and Swift UI that structs were going to be a big deal. I am used to structs being able to contain a collection of other types, but not methods. So I was confused at why tuples existed; that is now cleared up.

If structs can have methods as well as properties, it answers the question of why tuples exist, but immediately asks the question, why have classes since structs have all this power? I already know (from my podcast consumption) one of the answers for this is that structs are value types rather than references. When you:

Checkpoint 5

Sat, 16 Jul 2022 00:00:00 +0000

/*
 Your input is this:
 
 let luckyNumbers = [7, 4, 38, 21, 16, 15, 12, 33, 31, 49]
 
 Your job is to:
 
 Filter out any numbers that are even
 Sort the array in ascending order
 Map them to strings in the format “7 is a lucky number”
 Print the resulting array, one item per line
 
 So, your output should be as follows:
 
 7 is a lucky number
 15 is a lucky number
 21 is a lucky number
 31 is a lucky number
 33 is a lucky number
 49 is a lucky number
 */

let luckyNumbers = [7, 4, 38, 21, 16, 15, 12, 33, 31, 49]

func isNumberOdd(number:Int) -> Bool {
 return number%2 == 1
}

let filteredNumbers = luckyNumbers.filter(isNumberOdd)

// this closure effectively does nothing
let sortedNumbers = filteredNumbers.sorted(by: {$0<$1}) 

let mappedNumbers = sortedNumbers.map({ String($0)+" is a lucky number" })

for i in 0..<mappedNumbers.count {
 print(mappedNumbers[i])
}

Checkpoint 4

Wed, 13 Jul 2022 00:00:00 +0000

/*
 The challenge is this: write a function that accepts an integer from 1 through 10,000, and returns the integer square root of that number. That sounds easy, but there are some catches:
 
 You can’t use Swift’s built-in sqrt() function or similar – you need to find the square root yourself.
 If the number is less than 1 or greater than 10,000 you should throw an “out of bounds” error.
 You should only consider integer square roots – don’t worry about the square root of 3 being 1.732, for example.
 If you can’t find the square root, throw a “no root” error.
 */

enum IntSqrtError: Error {
 case low, high, noIntRoot
}

func calculateIntSqrt(_ number:Int) throws -> Int {
 let lowerBound = 1
 let upperBound = 10_000
 if number < lowerBound {throw IntSqrtError.low}
 if number > upperBound {throw IntSqrtError.high}
 // brute force sqrt finder
 for i in lowerBound...number {
 if i*i == number {
 return i
 }
 }
 // none found or we would have returned by now
 throw IntSqrtError.noIntRoot
}

do {
 try print(calculateIntSqrt(5929))
} catch IntSqrtError.low {
 print("Lower bound error")
} catch IntSqrtError.high {
 print("Upper bound error")
} catch IntSqrtError.noIntRoot {
 print("No integer root")
} catch {
 assert(false)
 print("Unknown error")
}

Tuple Pronunciation

Tue, 12 Jul 2022 00:00:00 +0000

Another advantage of the videos, that hadn’t occurred to me when I mentioned it the other day , is learning the correct pronunciation of things you’ve only ever read in books.

Apparently, tuple is pronounced two-pull, and not with the tup to rhyme with cup as I’d always imagined. Google has confirmed, so it’s not just a UK thing.

Watch or Read

Sun, 10 Jul 2022 00:00:00 +0000

I’m appreciating, in the 100 Days of Swift UI , that Paul Hudson has provided a video and a text description for each of the topics. Usually, I’ll read the text - a lot of these early topics cover ground well-trodden from my previous experience, so I can skim forwards to find the Swift specific bits I need. However, if I’m making up my hour per day of Swift by multitasking it with a meal, then the video is handy.

Checkpoint 3

Fri, 08 Jul 2022 00:00:00 +0000

 /*
 If it’s a multiple of 3, print “Fizz”
 If it’s a multiple of 5, print “Buzz”
 If it’s a multiple of 3 and 5, print “FizzBuzz”
 Otherwise, just print the number.
 */

for i in 1...100 {

 let isMultOfThree = (i % 3 == 0)
 let isMultOfFive = (i % 5 == 0)

 if (isMultOfFive && isMultOfThree) {
 print("FizzBuzz")
 } else if isMultOfThree {
 print("Fizz")
 } else if isMultOfFive {
 print("Buzz")
 } else {
 print(i)
 }
}

100 days of SwiftUI

Tue, 05 Jul 2022 00:00:00 +0000

Paul Hudson’s intro to his IOS development course asks participants to post on social media each day as part of an effort to keep them motivated. The Insta tag #100daysofswiftui is full of curated photos of MacBook Pros showing Xcode 14. This also seems like handy marketing for Paul.

It’s not a crazy idea, so I’ll add this to the long list of excitedly started and eventually abandoned blogs of the world. Perhaps a post will even help a forlorn google searcher out on day. I’ll aim to keep them short, so it does not become a large enough task to trigger it’s own procrastination.