如何修复“无法下标类型的值&#39;ClosedRange <Int> &#39;在swift中使用&#39;Int&#39;类型的索引

Question

I wanna prepare a basic number picker timer for my homework but I cannot fix this problem.

var timer = Timer()
    var counter = 0

    //let number = ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "30"]

    let number = 1 ... 60

    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 1
    }

    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        return number[row]
    }




    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return number.count
    }

    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        label.text = number[row]

    } 

But it gives this error.

Cannot subscript a value of type 'ClosedRange' with an index of type 'Int'

Answer 1

您正在创建一个数组，因此您需要在该范围内使用方括号。

let numbers = [1...60]

Answer 2

You need an array of strings [String] but you declare an integer range ClosedRange<Int>

Create an array from the range and map the items to String

let number = Array(1...60).map(String.init)

It's recommended to declare arrays in plural form let numbers

Answer 3

You can simply do:

let numbers = Array(1...60)

How does this work?

You can explore this yourself. A trick is to add the explicit init call:

Array.init(1...60)

and then option -click on init . When you do that, you get:

Summary

Creates an array containing the elements of a sequence. Declaration

 init<S>(_ s: S) where Element == S.Element, S : Sequence 

Discussion

You can use this initializer to create an array from any other type that conforms to the Sequence protocol. For example, you might want to create an array with the integers from 1 through 7. Use this initializer around a range instead of typing all those numbers in an array literal.

 let numbers = Array(1...7) print(numbers) // Prints "[1, 2, 3, 4, 5, 6, 7]"