Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

iOS Build a Simple iPhone App with Swift 2.0 Getting Started with iOS Development Swift Recap Part 1

Julien Schmitt
Julien Schmitt
2,334 Points
Posted by Julien Schmitt
Julien Schmitt
2,334 Points

Extract value in a struct?

Hi all,

Little obstacle I'm facing here.

The constant postDescription returns "iOSDevelopment by Apple. Filed under Tag(name: "swift")".

How can I get it to return "iOSDevelopment by Apple. Filed under swift" ?

Thanks,

Julien

structs.swift 
struct Post {
    let title: String
    let author: String
    let tag: Tag

    func description() -> String {
        return "\(title) by \(author). Filed under \(tag)"
    }
}

let firstPost = Post(title: "iOSDevelopment", author: "Apple", tag: Tag(name: "swift"))

let postDescription = firstPost.description()

4 Answers

jcorum
jcorum
71,830 Points

Julien, in the description method you need to give it a Tag object's name, not a Tag object:

struct Post {
    let title: String
    let author: String
    let tag: Tag

    func description() -> String {
        return "\(title) by \(author). Filed under \(tag.name)"
    }
}

let firstPost = Post(title: "iOSDevelopment", author: "Apple", tag: Tag(name: "swift"))

let postDescription = firstPost.description()
Julien Schmitt
Julien Schmitt
2,334 Points
Julien Schmitt
Julien Schmitt
2,334 Points

Hi jcorum,

Thanks for the help, it did work.

However could you explain me why we have to specify the .name ? If we refer to the tag structure that contains only one stored property that is name, why do we have to specify it?

Thanks in advance,

Julien

jcorum
jcorum
71,830 Points
jcorum
jcorum
71,830 Points

Julien, good question. tag is a Tag object, just like title is a String object. tag.name is a String. The default initializer expects String, String, Tag, but the function needs a String, i.e., tag.name

P.S., you could do this instead:

let tag = Tag(name: "swift")
let firstPost = Post(title: "iOS Development", author: "Apple", tag: tag)

Here you create the tag object first, and then pass it in as the 3rd parameter.

Julien Schmitt
Julien Schmitt
2,334 Points
Julien Schmitt
Julien Schmitt
2,334 Points

Thanks for your explanation !