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iOS

Posted by David Lett
David Lett
7,483 Points

Swift Collections Extra credit?

I'm trying to do the extra credit with the song titles and names, I like the way it's done in this example....

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

However, the [Dictionary<String, String>] is throwing me off. I read it wasn't necessary so how would it look minus that line?

1 Answer

Michael Hulet
Michael Hulet
47,913 Points

You could do without that in one of 2 ways. You could:

  • Format it differently, like this:
//Declaring it as [[String : String]] is exactly the same as declaring it as [Dictionary<String, String>], but with fewer characters
var songs: [[String : String]] = [
    [
        "title": "Back in Black",
        "artist": "Metallica",
        "album": "Neverland"
    ],
    [
        "title": "Back in Red",
        "artist": "Metallica",
        "album": "Neverland"
    ]
    // ...
]
  • Delete the explicit declaration altogether and let the compiler infer the type, like this:
//In this, you don't even tell the compiler what type songs is, but it can guess it itself
var songs = [
    [
        "title": "Back in Black",
        "artist": "Metallica",
        "album": "Neverland"
    ],
    [
        "title": "Back in Red",
        "artist": "Metallica",
        "album": "Neverland"
    ]
    // ...
]
David Lett
David Lett
7,483 Points

I was looking for the method that let the compiler infer the type. Just for future reference how would you call each arrary to display the title,artist and album?

Michael Hulet
Michael Hulet
47,913 Points

If you wanted to get the title of the first Dictionary in the Array, you would use this line, for example:

//The first set of square brackets (with the Int) specifies what Dictionary in the Array you want
                  |   //The second set of square brackets (with the String) specifies what index of the Dictionary you want
                  |     |
let black = songs[0]["title"]

The above would cause the constant black to be equal to the String "Back in Black"