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iOS

Kenton Hubner
Kenton Hubner
6,314 Points
Posted by Kenton Hubner
Kenton Hubner
6,314 Points

Swift extra credit challenge, dictionary

I wasn't sure what was exactly meant so I have two examples to see if either one was correct. 

import UIKit

var songList = ["Song One":"Abby Dabby",
                "Song Two":"Abby Dabby",
                "Song Three":"Abby Dabby",
                "Song Four":"Abby Dabby",
                "Song Five":"Abby Dabby",
                "Song Six":"Abby Dabby",
                "Song Seven":"Abby Dabby",
                "Song Eight":"Abby Dabby",
                "Song Nine":"Abby Dabby",
                "Song Ten":"Abby Dabby",]


// OR

let songOne = ["title" : "Back in Black", "Artist":"Metallica", "Album":"Neverland"]

let songTwo = ["title" : "Back in Red", "Artist":"Metallica", "Album":"Neverland"]

let songThree = ["title" : "Back in Blue", "Artist":"Metallica", "Album":"Neverland"]

let songFour = ["title" : "Back in Yellow", "Artist":"Metallica", "Album":"Neverland"]

let songFive = ["title" : "Back in Green", "Artist":"Metallica", "Album":"Neverland"]

let songSix = ["title" : "Back in Pink", "Artist":"Metallica", "Album":"Neverland"]

let songSeven = ["title" : "Back in White", "Artist":"Metallica", "Album":"Neverland"]

let songEight = ["title" : "Back in Orange", "Artist":"Metallica", "Album":"Neverland"]

let songNine = ["title" : "Back in Silver", "Artist":"Metallica", "Album":"Neverland"]

let songTen = ["title" : "Back in Brown", "Artist":"Metallica", "Album":"Neverland"]

var songArray = [songOne, songTwo, songThree, songFour, songFive, songSix, songSeven, songEight, songNine, songTen]

4 Answers

Chris Shaw
Chris Shaw
26,676 Points
Chris Shaw
Chris Shaw
26,676 Points

Hi Kenton,

Your second example is pretty much there apart of the key names, however to make it more explicit what the array contains I feel the below is what the extra credit is aiming for because dictionaries in Swift are explicit types so they can only carry one type based on the type assigned to it.

var songs: [Dictionary<String, String>] = [
    [
        "title": "Back in Black",
        "artist": "Metallica",
        "album": "Neverland"
    ],
    [
        "title": "Back in Red",
        "artist": "Metallica",
        "album": "Neverland"
    ]
    // ...
]

Personally this is how I would do it but the type assignment [Dictionary<String, String>] isn't required because Swift will infer the type during compilation but it's best to help it out wherever possible.

David kidd
David kidd
1,684 Points
David kidd
David kidd
1,684 Points

Thats a very elegant way to do this. Thanks for sharing. I did it like the OP's second method as i wasnt aware it could be completed this way.

Kenton Hubner
Kenton Hubner
6,314 Points
Kenton Hubner
Kenton Hubner
6,314 Points

Thanks! I didn't know I could string them together like that.

Meg Cusack
Meg Cusack
11,448 Points
Meg Cusack
Meg Cusack
11,448 Points

Thanks, this was very helpful. Does Treehouse actually post the answers to their extra credits somewhere? It would be nice to see it.

David Lett
David Lett
7,483 Points
David Lett
David Lett
7,483 Points

So can you do this without the [Dictionary<String, String>] and just start from the first array? Also how would you call each song if you wanted to display the results?

michael de marigny
michael de marigny
3,411 Points
michael de marigny
michael de marigny
3,411 Points

Hi Chris

Thank you for your example to the solution. My question is how would you add to the dictionary using inserts, appends and removes? Would you be able to provide some samples?

thanks