swift - 无法将字符串分配给我的 Swift 函数中的数组元素

Question

下面代码中的两个分配行都给我这个错误:

'@|value $T5' is not identical to 'String'

   func PrintShoppingList(myList: Array<String>)
    {
        println(myList)
        var cabbage = "cabbage"
        let fish:String = "fish"
        myList[0] = cabbage
        myList[1] = fish
    }

怎么了？

Answer 1

默认情况下，参数是常量，您不能更改它们。您可以将它们更改为 var，但这将是数组的副本。

func PrintShoppingList(var myList: Array<String>)
{
    println(myList)
    var cabbage = "cabbage"
    let fish:String = "fish"
    myList[0] = cabbage
    myList[1] = fish
}

你也可以使用inout参数来改变原始值，但是记住数组长度不能被上标扩展，所以myList[1] = fish会崩溃案例。

func PrintShoppingList(inout myList: Array<String>)
{
    println(myList)
    var cabbage = "cabbage"
    let fish:String = "fish"
    myList[0] = cabbage
    myList.append(fish)
}