Immutable value of Array only has mutating members named append

Question

This error pops up :

Immutable value of [PrizeItem] only has mutating members named append on the code line : prizesList.append(randomPrize)

 func openPrizeBox(){

        let prizeCycleCount = randomNumberInRange(8, 20) //<-Returns random Int
        let timeInterval = NSTimeInterval(prizeCycleCount)

        let prizesList : [PrizeItem] = []

        for var i = 0; i < prizeCycleCount; i++  {
            let randomPrize = prizeItems[randomNumberInRange(0, prizeItems.count-1)]
            prizesList.append(randomPrize) //Shows error here
        }

This is the PrizeItem Struct

struct PrizeItem {

enum Rank {
    case Ok
    case Good
    case Epic
    case Rare
    case ExtremelyRare
}

var name : String
var description : String

let rank : Rank


var identifier: String

}

Array:

let prizeItems : [PrizeItem] = [

PrizeItem(name: "Laser", description: "Test Item", rank: PrizeItem.Rank.Good, identifier: "laser")

]

If you can help me that would be great! Thank you very much!!!

Did you read about let vs var in the Swift book?

Martin R
– Martin R

2015-08-26 16:40:58 +00:00
Commented Aug 26, 2015 at 16:40 — Martin R
– Martin R, Commented Aug 26, 2015 at 16:40
@MartinR What do i need to do?

Entitize
– Entitize

2015-08-26 16:43:25 +00:00
Commented Aug 26, 2015 at 16:43 — Entitize
– Entitize, Commented Aug 26, 2015 at 16:43

Lamour · Accepted Answer · 2015-08-26 17:10:36Z

1

When you use let you cannot change or append or add new things to this variable.Therefore in this line :

let prizesList : [PrizeItem] = []

should be change to

var prizesList : [PrizeItem] = []

Important Using let only when you need to this value to be constant

answered Aug 26, 2015 at 17:10

Lamour

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1 Comment

Entitize Over a year ago

Thanks! You made my day. That was a stupid mistake. XD I spent a long hour removing and editing code. Thanks for your help!

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