Swift: Addition between value when duplicate strings in an array

Question

Let's say I have an array that looks like this:

let games = [
  Game(type: "Soccer", value: 1),
  Game(type: "Basket", value: 3),
  Game(type: "Hockey", value: 5),
  Game(type: "Soccer", value: 2),
  Game(type: "Soccer", value: 4),
  Game(type: "Basket", value: 2)
]

I want a new array with 1 row per type with the values added to each other with matching type. Something like this:

let newGames = [
  NewGame(type: "Soccer", value: 7),
  NewGame(type: "Basket", value: 5),
  NewGame(type: "Hockey", value: 5)
]

Help please. My brain is not cooperating.

rob mayoff · Accepted Answer · 2015-11-02 20:43:25Z

3

struct Game {
    let type: String
    let value: Int
}

let games: [Game] = [
    Game(type: "Soccer", value: 1),
    Game(type: "Basket", value: 3),
    Game(type: "Hockey", value: 5),
    Game(type: "Soccer", value: 2),
    Game(type: "Soccer", value: 4),
    Game(type: "Basket", value: 2)
]

var totalValueForGame = [String: Int]()
for game in games {
    totalValueForGame[game.type] = game.value + (totalValueForGame[game.type] ?? 0)
}

let newGames = totalValueForGame.map { Game(type: $0, value: $1) }
print(newGames)

Output:

[Game(type: "Soccer", value: 7), Game(type: "Hockey", value: 5), Game(type: "Basket", value: 5)]

answered Nov 2, 2015 at 20:43

rob mayoff

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Comments

Leo Dabus · Accepted Answer · 2015-11-02 22:31:01Z

1

class Game {
    var type: String
    var value: Int
    init(type: String, value: Int) {
        self.type = type
        self.value = value
    }
}

let games: [Game] = [
    Game(type: "Soccer", value: 1),
    Game(type: "Basket", value: 3),
    Game(type: "Hockey", value: 5),
    Game(type: "Soccer", value: 2),
    Game(type: "Soccer", value: 4),
    Game(type: "Basket", value: 2)
]
var gameTotals:[Game] = []
for key in Set(games.map{$0.type}) {
    gameTotals.append(Game(type: key, value: games.filter{$0.type == key}.reduce(0){$0+$1.value}))
}

gameTotals  // [{type "Soccer", value 7}, {type "Hockey", value 5}, {type "Basket", value 5}]

edited Nov 2, 2015 at 22:31

answered Nov 2, 2015 at 22:13

Leo Dabus

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Comments

Andi Utzinger · Accepted Answer · 2015-11-02 21:13:41Z

My (ugly) solution :D :D

import Cocoa

class Game {
    var name:String
    var value:Int

    init(withName aName:String, andValue value:Int) {
        self.name = aName
        self.value = value
    }
}

var someSports:[Game] = []
var tempDictOfGames:[String:Int] = [:]


var sports:[String] = ["Soccer", "Volleyball", "Tennis", "Rugby", "Tennis", "Soccer", "Tennis", "Cricket"]
var values:[Int] = [1, 5, 3, 8, 2, 9, 4, 7]


for (var i = 0; i < sports.count; i++) {

    var availableGameValue:Int? = tempDictOfGames[sports[i]]

    if let myValue = availableGameValue {
        tempDictOfGames[sports[i]]! += values[i]
    } else {
        tempDictOfGames[sports[i]] = values[i]
    }
}

for (k, v) in tempDictOfGames {
    let newGame = Game(withName: k, andValue: v)
    someSports.append(newGame)
}

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