Question

我很困惑。

我可以使用以下方法循环使用类型转换的数组：

for case let provider as ProviderModel in providers {
    provider.activated = true
}

但是我怎么能在这里实现索引Swift风格呢？像这样：

for (index, provider <<type cast>>) in providers.enumerated() {
    provider.activated = true
}

Answer 1

使用元组模式：

for case (let offset, let provider as ProviderModel) in providers.enumerated() {
    // ...
}

或等效地：

for case let (offset, provider as ProviderModel) in providers.enumerated() {
    // ...
}

一个独立的例子：

let numbersAndStrings: [Any] = [1, "2", 3, "4", 5]

for case let (offset, number as Int) in numbersAndStrings.enumerated() {
    print(number, "at offset", offset)
}

输出：

1 at offset 0
3 at offset 2
5 at offset 4

for case让我们使用enumerated（）方法

1 个答案: