如何在用户的区域设置中获取星期几的名称？

Question

我有一个介于1和7之间的数字，我希望将其转换为用户的语言环境，相当于周一到周日。我可以这样做，如果是这样，怎么样？

Answer 1

NSDateFormatter可以为您提供名称列表：

NSDateFormatter * df = [[NSDateFormatter alloc] init];
[df setLocale: [NSLocale currentLocale]];
NSArray * weekdays = [df weekdaySymbols];

然后，你可以像任何其他数组一样索引[weekdays objectAtIndex:dayIdx];但是，请注意，the first weekday可能因地区而异;究竟如何变化（以及关于NSCalendar的许多其他事情）在文档中没有特别好的解释。

Answer 2

当然可以。下面是一个方法/函数，它返回0到6范围内工作日编号的工作日名称。

Objective C版本：

- (NSString *)weekdayNameFromWeekdayNumber:(NSInteger)weekdayNumber
{
    NSCalendar *calendar = [NSCalendar currentCalendar];

    // Fetch the days of the week in words for the current language (Sunday to Saturday)
    NSArray *weekdaySymbols = calendar.weekdaySymbols;

    // Because the first week day changes depending on the region settings.
    //  ie. In Bangladesh the first day of the week is Friday. In UK it is Monday
    NSInteger index = (weekdayNumber + calendar.firstWeekday - 1) % 7;
    return weekdaySymbols[index];
}

和Swift 2版本：

func weekdayNameFromWeekdayNumber(weekdayNumber: Int) -> String {
    let calendar = NSCalendar.currentCalendar()
    let weekdaySymbols = calendar.weekdaySymbols
    let index = (weekdayNumber + calendar.firstWeekday - 1) % 7
    return weekdaySymbols[index]
}

和Swift 3.0版本：

func weekdayNameFrom(weekdayNumber: Int) -> String {
    let calendar = Calendar.current
    let weekdaySymbols = calendar.weekdaySymbols
    let index = (weekdayNumber + calendar.firstWeekday - 1) % 7
    return weekdaySymbols[index]
}

Answer 3

这是我的看法：

Swift 3，iOS8 +

func weekdayNameFrom(weekdayNumber: Int) -> String {
    let calendar = Calendar.current
    let dayIndex = ((weekdayNumber - 1) + (calendar.firstWeekday - 1)) % 7
    return calendar.weekdaySymbols[dayIndex]
}

请注意，您有3个可用列表：

• weekdaySymbols - > ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"]
• shortWeekdaySymbols - > ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"]
• veryShortWeekdaySymbols - > ["S", "M", "T", "W", "T", "F", "S"]

Answer 4

NSArray *weekdaySymbols = [[NSDateFormatter alloc] weekdaySymbols];

您可以使用{weekdaySymbols，shortWeekdaySymbols，veryShortWeekdaySymbols}之一

Answer 5

我找到了这个解决方案：你有你的日期对象，你希望得到该对象的一周中的那一天。

1. 将语言环境设置为日期格式化程序，如下所示

   let eventDate = dateFormatter.date(from: self)
   let language = Locale.preferredLanguages.first
   print("The locale id is  \(language)")
   // This date format can be what ever you like, in this case i used EE dd
   dateFormatter.dateFormat = "EE dd"
   if let idiomaLocale = language {
       dateFormatter.locale = Locale(identifier: idiomaLocale)
   } else {
       dateFormatter.locale = Locale(identifier: "es_CO")
   }

2. 这样做可以确保您获得了日期格式化程序的正确标识符，之后配置了日期格式化程序，您可以继续并获取星期几的字符串

   //convert your date to string
   let stringDate = dateFormatter.string(from: eventDate!)
   
   return stringDate

我希望这有助于某人:)。新年快乐。

Answer 6

基于gavdotnet优秀的解决方案，欧洲版（从周一开始）是：

func weekdayNameFromWeekdayNumber(weekdayNumber: Int) -> String {
    var EuroDay = weekdayNumber + 1
    if EuroDay == 7 {
        EuroDay = 0
    }
    let calendar = NSCalendar.currentCalendar()
    let weekdaySymbols = calendar.weekdaySymbols
    let index = EuroDay + calendar.firstWeekday - 1
    return weekdaySymbols[index].uppercaseString
}