Question

这是一个非常简单的问题，我正在使用代码段

获取一周的一天

 if let weekday = getDayOfWeek("2017-05-01") {
        print(weekday)
    } else {
        print("bad input")
    }


func getDayOfWeek(_ today:String) -> Int? {
    let formatter  = DateFormatter()
    formatter.dateFormat = "yyyy-MM-dd"
    guard let todayDate = formatter.date(from: today) else { return nil }
    let myCalendar = Calendar(identifier: .gregorian)
    let weekDay = myCalendar.component(.weekday, from: todayDate)
    return weekDay
}

我需要创建“工作日”，因为全局变量可以提供帮助。

我做的是：

class ViewController: UIViewController{
var weekday = NSInteger()
}

我在声明上面时收到了一些错误。

Answer 1

将currentWeekDay类型声明为Int。

var weekday = Int()

现在使用if let访问此实例属性。

if let weekday = getDayOfWeek("2017-05-01") {
    //weekday has block scope and available only with in this if block
    self.weekday = weekday
} else {
    print("bad input")
}

修改：设置timezone以获得正确的工作日

func getDayOfWeek(_ today:String) -> Int? {
    let formatter = DateFormatter()
    formatter.dateFormat = "yyyy-MM-dd"
    formatter.timeZone = TimeZone(abbreviation: "UTC")!
    guard let todayDate = formatter.date(from: today) else { return nil }
    let myCalendar = Calendar(identifier: .gregorian)
    let weekDay = myCalendar.component(.weekday, from: todayDate)
    return weekDay 
}

如何声明全局变量？

1 个答案: