swift - for if in swift 更优雅的代码

Question

我得到了一个简单的代码，它可以工作，我正在用老式的方式编程，我相信有一种更优雅的方式可以快速地做到这一点。这是代码:

    var cardsInCompartment1:Int = 0
    var cardsInCompartment2:Int = 0
    for card in cards{
        if card.compartment == 1{
            cardsInCompartment1 += 1
            print(cardsInCompartment1)
        }
        if card.compartment == 2{
            cardsInCompartment2 += 1
            print(cardsInCompartment2)
        }
    }

我基本上是在不同的隔间里拿到了卡片，现在我想数一数每个隔间里有多少张卡片。

Answer 1

如何使用 filter 来选择您想要的卡片？然后你可以计算它们:

let cardsInCompartment1 = cards.filter { $0.compartment == 1 }.count
let cardsInCompartment2 = cards.filter { $0.compartment == 2 }.count

---

如果你有一堆隔间，你可以将计数存储在字典中:

var compartmentCounts = [Int:Int]()

cards.forEach {
    compartmentCounts[$0.compartment] = (compartmentCounts[$0.compartment] ?? 0) + 1
}

在这种情况下，键是隔间#，值是卡数。类似于 [1: 32, 2: 42] 如果每个隔间中有 32 和 42 张卡片。