Reactive Programming in iOS with Combine

Feb 4 2021 · Swift 5.3, macOS 11.0, Xcode 12.2

Part 3: Combining Operators

17. Challenge: Append and Prepend

Episode complete

Play next episode

Next
About this episode

Leave a rating/review

See forum comments
Cinema mode Mark complete Download course materials
Previous episode: 16. Append Next episode: 18. More Combining Operators

Get immediate access to this and 4,000+ other videos and books.

Take your career further with a Kodeco Personal Plan. With unlimited access to over 40+ books and 4,000+ professional videos in a single subscription, it's simply the best investment you can make in your development career.

Learn more Already a subscriber? Sign in.

Heads up... You've reached locked video content where the transcript will be shown as obfuscated text.

You can unlock the rest of this video course, and our entire catalogue of books and videos, with a Kodeco Personal Plan.

Unlock now

You’ve learned all about Prepending and Appending operators - so now it’s time for a challenge. Back in the day, phone numbers used to be a lot easier to remember! 7 digits (in the United States, at least) was all you needed to remember to call your best friend. Now you need area codes, and if you’re calling a business, you’ll probably need to know a person’s extension, and if the number was long distance, you’d need to prepend a “1” in front of it. So for this challenge:

example(of: "Making Phone Numbers") {

  let phoneNumbersPublisher = ["123-4567"].publisher
  let areaCode = "410"
  let phoneExtension = "901"

  phoneNumbersPublisher
    .prepend("1-", areaCode, "-")
    .append(" EXT ")
    .append(phoneExtension)
    .collect()
    .sink(receiveValue:
    {
      print($0.joined())
    })
    .store(in: &subscriptions)
}