Swift - Convert Array to Dictionary

Question

I just want convert an array of Player Names into a dictionary Scoreboard, giving everyone an initial score of 0.

Meaning...

var playerNames = ["Harry", "Ron", "Hermione"]

becomes...

var scoreBoard: [String:Int] = [ "Ron":0, "Harry":0, "Hermione":0 ]

This is my first time asking a question, but I’m totally completely stuck on what feels so simple and all how-to's/questions I've found are off in some way. I have tried using reduce in a variety of ways, but always end up short. Thanks in advance!

Answer 1

Here's a quick one liner that I like to use:

let scoreboard = playerNames.reduce(into: [String: Int]()) { $0[$1] = 0 }

Answer 2

If the player names are known to be all different then you can do

let playerNames = ["Harry", "Ron", "Hermione", "Ron"]

var scoreBoard = Dictionary(uniqueKeysWithValues: zip(playerNames,
                                                      repeatElement(0, count: playerNames.count)))

print(scoreBoard) // ["Harry": 0, "Ron": 0, "Hermione": 0]

Here zip is used to create a sequence of player/score pairs, from which the dictionary is created.

Remark: Originally I had used AnySequence { 0 } to generate the zeros. Using repeatElement() instead was suggested by Alexander and has the advantage that the correct required capacity is passed to the dictionary intializer.