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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

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

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

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

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

Thanks for your explanation !