Xcode 8和Swift 3 NSCalendar

Question

我在Swift中实现了我的监视项目，现在我正在迁移到Swift 3，因为Xcode 8。我让Xcode 8将源代码更改为Swift 3.但是，代码中存在错误，我想不明白。

let unitFlags: Calendar = [.hour, .firstWeekday, .monthSymbols, .year, .minute, .firstWeekday] 

var calendar = NSCalendar.current 
calendar.timeZone = NSTimeZone(identifier: "UTC")! 
let components = (calendar as NSCalendar).components(unitFlags, from: reservationDate) 

Xcode在这些行中给出错误，我无法理解这个问题。

ERROR: Contextual type ' Calendar' cannot be used with array literal

ERROR: Argument labels '(identifier:)' do not match any available overloads

ERROR: Cannot convert value of type 'Calendar' to expected argument type 'NSCalendar.Unit'

Answer 1

首先，既不NSCalendarUnit在夫特2也不Calendar.Component在夫特3包含的组件firstWeekday和monthSymbols。

在斯威夫特3代码相当于是

let unitFlags = Set<Calendar.Component>([.hour, .year, .minute]) 
var calendar = Calendar.current 
calendar.timeZone = TimeZone(identifier: "UTC")! 
let components = calendar.dateComponents(unitFlags, from: reservationDate) 

Answer 2

变化unitFlags的类型设置