arrays - 索引可能不存在(textField)swift xcode

Question

基本上，描述是一个可选输入，当存在“葡萄绿”等输入时，会抛出“无效索引范围”等错误。除了添加额外的文本字段之外，还有其他方法可以解决此问题吗？

let fruits = "\(textField.text!)"
let fruitsArray = fruits.split(separator: " ")
let fruitName = "\(fruitsArray[0])"
let fruitColour = "\(fruitsArray[1])"
let description = "\(fruitsArray[2])"

Answer 1

对于这种情况(仍然发现在单个文本字段中要求三个不同的属性不太明智)，我建议为 fruit 实现一个模板> 事情。示例:

struct Fruit {
    var name: String?
    var colour: String?
    var description: String?

    init?(string: String) {
        let array = string.trimmingCharacters(in: .whitespacesAndNewlines).components(separatedBy: " ").filter { !$0.isEmpty }
        switch array.count {
        case 3...:
            fallthrough
        case 3:
            description = array[2]
            fallthrough
        case 2:
            colour = array[1]
            fallthrough
        case 1:
            name = array[0]

        default:
            return nil
        }
    }
}

此时，您可以通过传递字符串来声明一个 Fruit 实例；因此:

let string = "Grapes green"
let fruit = Fruit(string: string)
print(fruit)
// Optional(__lldb_expr_21.Fruit(name: Optional("Grapes"), colour: Optional("green"), description: nil))