索引超出范围将日期转换为字符串组件

Question

我知道这是一个微不足道的错误，但我无法弄清楚，我被卡住了。
我想为 UISegmentedControl（有 6 个段）分配第一个段中的当前日期和下一个段中接下来的 5 天日期，如下图所示。为此，我需要从日期构造一个字符串数组，但我在这一行 let dayString = dateFormatter.shortWeekdaySymbols[dayComponent-1]

上得到的索引超出范围

var stringDates = [String]()
override func viewDidLoad() {
    super.viewDidLoad()


//for each segment, construct a string date with the currentDate() being first
    for i in 1...6 {

        let dateFormatter = DateFormatter()

        let today = Date()
        let calendar = Calendar.current

        if i == 1 {
           let dayComponent = Calendar.current.component(.day,from: today)
             let dayString = dateFormatter.shortWeekdaySymbols[dayComponent-1]  
               let month = Calendar.current.component(.month, from: today)
                let monthSymbol = dateFormatter.shortMonthSymbols[month-1]

                   let dayMonthString = dayString + monthSymbol
                         stringDates.append(dayMonthString)
        } else {
           var components = DateComponents()
           components.weekday = i
            let nextDay = calendar.date(byAdding: components, to: today)
              let dayComponent = Calendar.current.component(.day,from: nextDay!)
                let dayString = dateFormatter.shortWeekdaySymbols[dayComponent-1]

            let month = Calendar.current.component(.month, from: nextDay!)
              let monthSymbol = dateFormatter.shortMonthSymbols[month-1]
               let dayMonthString = dayString + monthSymbol
                  stringDates.append(dayMonthString)
         }          
    }
  }

Answer 1

而不是 let dayComponent = Calendar.current.component(.day,from: today) 中的 .day 使用 .weekday，如下所示：

let today = Date()
let dateFormatter = DateFormatter()
let dayComponent = Calendar.current.component(.weekday,from: today)
let dayString = dateFormatter.shortWeekdaySymbols[dayComponent - 1]  //Fri

Answer 2

崩溃的原因是 shortWeekdaySymbols[] 只能取 0 到 6 之间的值。

shortWeekdaySymbols[0] = sun
shortWeekdaySymbols[1] = mon

等等。

let stringArray = [String]()
for value in 1 ..< 6 {

let today = Date()
let tomrow = Calendar.current.date(byAdding: .day, value: value, to:today)
let dateFormatter = DateFormatter()
let dayComponent = Calendar.current.component(.weekday,from: tomrow!)
    let day = Calendar.current.component(.day, from: tomrow!)

    let month = Calendar.current.component(.month, from: tomrow!)
    let dayString = dateFormatter.shortWeekdaySymbols[dayComponent - 1]
    let monthString = (dateFormatter.shortStandaloneMonthSymbols[month - 1])
    let FullDate =  String(day) + " " + monthString +  " " + dayString
    print(FullDate)
}

索引超出范围将日期转换为字符串组件

Index out of range convert date to string component

arrays

for-loop

uisegmentedcontrol

swift