xcode 无法分配给属性：'card' 是 swift for 循环中的 'let' 常量
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Cannot assign to property: 'card' is a 'let' constant in a for loop in swift
提问by sriram hegde
Cannot assign to property: 'card' is a 'let' constant in for loop in chooseCard method. I am not able to figure out why the error is coming in the for loop .what am I missing in the code .Please help.
无法分配给属性：'card' 是chooseCard 方法中 for 循环中的一个 'let' 常量。我无法弄清楚为什么错误会出现在 for 循环中。我在代码中遗漏了什么。请帮忙。
import Foundation
class Concentration {
var cards = [Card]()
var faceUpCount = 0
func chooseCard(atIndex : Int) {
var alreadyFaceUpCard = Card()
if faceUpCount == 0 {
alreadyFaceUpCard = cards[atIndex]
alreadyFaceUpCard.isFaceUp = true
faceUpCount += 1
}else if faceUpCount == 1 {
var card = cards[atIndex]
card.isFaceUp = true
if alreadyFaceUpCard.identifier == card.identifier {
alreadyFaceUpCard.isMatchUp = true
card.isMatchUp = true
faceUpCount += 1
}
}else {
for card in cards {
card.isFaceUp = false
}
}
}
init(numberOfPairsOfCards : Int) {
for _ in 1...numberOfPairsOfCards {
let card = Card()
cards.append(card)
cards.append(card)
}
// TODO: Shuffle Cards
}
}
回答by Madhur
card is ofcourse a let constant, to make it variable use: for var card in cards
卡当然是一个让常量，使其可变使用： for var card in cards
