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iOS

Joel Crouse
Joel Crouse
4,727 Points
Posted by Joel Crouse
Joel Crouse
4,727 Points

How to randomize a dictionary and display the keys and values

Example: I have a dictionary of songs where the key is the song title and the value is the artist.

let songs = ["Song Title": "Artist", "Song Title": "Artist", "Song Title": "Artist"]

In my view I have two labels, one for the song title and one for the artist and I want to populate each label with a song title and corresponding artist from the dictionary randomly after a user taps a button.

So far I've creating the IBOutlets for each label and an IBAction for the button so I just need to create a function that pulls out a random song from the dictionary and allows me to access the songs title (key) and artist (value). How could I do this?

2 Answers

Chris Stromberg
PLUS
Chris Stromberg
Courses Plus Student 13,389 Points
Chris Stromberg
Chris Stromberg
Courses Plus Student 13,389 Points 
let musicLibrary = ["Comfortably Numb": "Pink Floyd", "Hells Bells": "AC DC", "Lonely Boy": "The Black Keys"]

func randomSongFrom( musicLibrary library: [String: String]) -> String {

    // Gets song titles and places into an array, so that song titles can be picked randomly by index.
    var songs = Array(library.keys)

    // Generates random number to place for index value in song array.
    let randomNumber = GKRandomSource.sharedRandom().nextInt(upperBound: songs.count)

    let song = songs[randomNumber]
    let artist = library[song]

    return "Now playing \"\(song)\" by \(artist ?? "No Artist")."

}

randomSongFrom(musicLibrary: musicLibrary)
randomSongFrom(musicLibrary: musicLibrary)
Joel Crouse
Joel Crouse
4,727 Points
Joel Crouse
Joel Crouse
4,727 Points

Why did you declare the songs variable from outside the function?

And why is the return statement formatted that way?

return "Now playing \"\(song)\" by \(artist ?? "No Artist")."
Jhoan Arango
Jhoan Arango
14,575 Points
Jhoan Arango
Jhoan Arango
14,575 Points

Hello,

To extend on Chri's answer..

You may want to also do it this way since you mentioned that you want to populate some fields. Instead of returning just a string you could return a tuple with the title and artist information about the song. 

import GameplayKit
// In order for you to be able to use GKRandomeSource you have to import GameplayKit

let library = ["Beat it": "Michael Jackson", "Like a Virgin": "Madonna", "Mine": "Bazzi"]

func randomSongFrom(_ library: [String: String]) -> (title: String, artist: String) {
    let titles = Array(library.keys)

    let randomIndex = GKRandomSource.sharedRandom().nextInt(upperBound: titles.count)

    let title = titles[randomIndex]
    let artist = library[title] ?? "Unknown"

    return (title , artist)

}

// Getting the random song

let song = randomSongFrom(library)

// Breaking down the song

let title = song.title
let artist = song.artist

Good luck, hope you find this useful