我正在开发一个应用程序，需要检查作业的截止日期。我想知道截止日期是否在下周内，如果是，则执行操作。 我能找到的大部分文档都在Objective-C中，我无法弄清楚如何在Swift中完成它。谢谢您的帮助！！
我喜欢使用扩展来使代码更具可读性。以下是一些NSDate扩展，可以帮助您清理代码并使其易于理解。我把它放在sharedCode.swift文件中：
extension NSDate {
func isGreaterThanDate(dateToCompare: NSDate) -> Bool {
//Declare Variables
var isGreater = false
//Compare Values
if self.compare(dateToCompare as Date) == ComparisonResult.orderedDescending {
isGreater = true
}
//Return Result
return isGreater
}
func isLessThanDate(dateToCompare: NSDate) -> Bool {
//Declare Variables
var isLess = false
//Compare Values
if self.compare(dateToCompare as Date) == ComparisonResult.orderedAscending {
isLess = true
}
//Return Result
return isLess
}
func equalToDate(dateToCompare: NSDate) -> Bool {
//Declare Variables
var isEqualTo = false
//Compare Values
if self.compare(dateToCompare as Date) == ComparisonResult.orderedSame {
isEqualTo = true
}
//Return Result
return isEqualTo
}
func addDays(daysToAdd: Int) -> NSDate {
let secondsInDays: TimeInterval = Double(daysToAdd) * 60 * 60 * 24
let dateWithDaysAdded: NSDate = self.addingTimeInterval(secondsInDays)
//Return Result
return dateWithDaysAdded
}
func addHours(hoursToAdd: Int) -> NSDate {
let secondsInHours: TimeInterval = Double(hoursToAdd) * 60 * 60
let dateWithHoursAdded: NSDate = self.addingTimeInterval(secondsInHours)
//Return Result
return dateWithHoursAdded
}
}
现在，如果你能做到这样的事情：
//Get Current Date/Time
var currentDateTime = NSDate()
//Get Reminder Date (which is Due date minus 7 days lets say)
var reminderDate = dueDate.addDays(-7)
//Check if reminderDate is Greater than Right now
if(reminderDate.isGreaterThanDate(currentDateTime)) {
//Do Something...
}
这个函数对我有用，可以比较一个日期（startDate）是否在endDate之后，两者都被定义为NSDate变量：
if startDate.compare(endDate as Date) == ComparisonResult.orderedDescending
在Swift实施
let documentsPath = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as NSString
let files = NSFileManager.defaultManager().contentsOfDirectoryAtPath(documentsPath, error: nil)
let filesAndProperties = NSMutableArray()
for file in files! {
let filePath = documentsPath.stringByAppendingString(file as NSString)
let properties = NSFileManager.defaultManager().attributesOfItemAtPath(filePath, error: nil)
let modDate = properties![NSFileModificationDate] as NSDate
filesAndProperties.addObject(NSDictionary(objectsAndKeys: file, "path", modDate, "lastModDate"))
}
let sortedFiles = filesAndProperties.sortedArrayUsingComparator({
(path1, path2) -> NSComparisonResult in
var comp = (path1.objectForKey("lastModDate") as NSDate).compare(path2.objectForKey("lastModDate") as NSDate)
if comp == .OrderedDescending {
comp = .OrderedAscending
} else if comp == .OrderedAscending {
comp = .OrderedDescending
}
return comp
})
var dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
let dateData: String = dateFormatter.stringFromDate(date1)
let testDate: String = dateFormatter.stringFromDate(date2)
print(dateData == testDate)
我们有情况检查当前时间是否是两次（两个日期）。例如，我想检查诊所（医院）开放时间和关闭时间之间的当前谎言。
使用简单的代码。
NSDate * now = [NSDate date];
NSDateFormatter *outputFormatter = [[NSDateFormatter alloc] init];
[outputFormatter setDateFormat:@"HH:mm:ss"];
//current time
NSString *currentTimeString = [outputFormatter stringFromDate:now];
NSDate *dateCurrent = [outputFormatter dateFromString:currentTimeString];
NSString *timeStart = @"09:00:00";
NSString *timeEnd = @"22:00:00";
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"HH:mm:ss"];
NSDate *dateStart= [formatter timeStart];
NSDate *dateEnd = [formatter timeEnd];
NSComparisonResult result = [dateCurrent compare:dateStart];
NSComparisonResult resultSecond = [date2 compare:dateEnd];
if(result == NSOrderedDescending && resultSecond == NSOrderedDescending)
{
NSLog(@"current time lies in starting and end time");
}else {
NSLog(@"current time doesn't lie in starting and end time");
}
对于swift 3，您可以使用以下函数比较两个日期。
func compareDate(dateInitial:Date, dateFinal:Date) -> Bool {
let order = Calendar.current.compare(dateInitial, to: dateFinal, toGranularity: .day)
switch order {
case .orderedSame:
return true
default:
return false
}
}
toGranularity可以根据您要应用比较的约束进行更改。
扩展SashaZ
Swift iOS 8及以上当您需要的不只是更大或更小的日期比较。例如，它是在同一天或前一天，......
注意：永远不要忘记时区。日历时区有默认值，但如果您不喜欢默认值，则必须自己设置时区。要知道它是哪一天，您需要知道您要问的时区。
extension Date {
func compareTo(date: Date, toGranularity: Calendar.Component ) -> ComparisonResult {
var cal = Calendar.current
cal.timeZone = TimeZone(identifier: "Europe/Paris")!
return cal.compare(self, to: date, toGranularity: toGranularity)
}
}
像这样使用它：
if thisDate.compareTo(date: Date(), toGranularity: .day) == .orderedDescending {
// thisDate is a previous day
}
一个更复杂的例子。查找并过滤数组中的所有日期，这些日期与“findThisDay”同一天：
let formatter = DateFormatter()
formatter.timeZone = TimeZone(identifier: "Europe/Paris")
formatter.dateFormat = "yyyy/MM/dd HH:mm:ss"
let findThisDay = formatter.date(from: "2018/11/05 08:11:08")!
_ = [
formatter.date(from: "2018/12/05 08:08:08")!,
formatter.date(from: "2018/11/05 08:11:08")!,
formatter.date(from: "2018/11/05 11:08:22")!,
formatter.date(from: "2018/11/05 22:08:22")!,
formatter.date(from: "2018/11/05 08:08:22")!,
formatter.date(from: "2018/11/07 08:08:22")!,
]
.filter{ findThisDay.compareTo(date: $0 , toGranularity: .day) == .orderedSame }
.map { print(formatter.string(from: $0)) }
someArray.sort({($0.dateAdded?.timeIntervalSinceReferenceDate)! < ($1.dateAdded?.timeIntervalSinceReferenceDate)!})
dateAdded是我的对象中的NSDate变量
class MyClass {
let dateAdded: NSDate?
}
如果你想为==s支持<，>，<=，>=或NSDate，你只需要在某处声明：
public func ==(lhs: NSDate, rhs: NSDate) -> Bool {
return lhs === rhs || lhs.compare(rhs) == .OrderedSame
}
public func <(lhs: NSDate, rhs: NSDate) -> Bool {
return lhs.compare(rhs) == .OrderedAscending
}
extension NSDate: Comparable { }
这是你在Swift中比较两个NSDates的方法，我刚在Xcode的游乐场测试过：
if date1.compare(date2) == NSComparisonResult.OrderedDescending
{
NSLog("date1 after date2");
} else if date1.compare(date2) == NSComparisonResult.OrderedAscending
{
NSLog("date1 before date2");
} else
{
NSLog("dates are equal");
}
因此，检查日期dueDate是否在一周内：
let dueDate=...
let calendar = NSCalendar.currentCalendar()
let comps = NSDateComponents()
comps.day = 7
let date2 = calendar.dateByAddingComponents(comps, toDate: NSDate(), options: NSCalendarOptions.allZeros)
if dueDate.compare(date2!) == NSComparisonResult.OrderedDescending
{
NSLog("not due within a week");
} else if dueDate.compare(date2!) == NSComparisonResult.OrderedAscending
{
NSLog("due within a week");
} else
{
NSLog("due in exactly a week (to the second, this will rarely happen in practice)");
}
我总是在一行中做到：
let greater = date1.timeIntervalSince1970 < date2.timeIntervalSince1970
仍然可以在if块中读取
在Swift3中，Date中的Foundation结构现在实现了Comparable协议。因此，以前的Swift2 NSDate方法被Swift3 Date取代。
/**
`Date` represents a single point in time.
A `Date` is independent of a particular calendar or time zone. To represent a `Date` to a user, you must interpret it in the context of a `Calendar`.
*/
public struct Date : ReferenceConvertible, Comparable, Equatable {
// .... more
/**
Returns the interval between the receiver and another given date.
- Parameter another: The date with which to compare the receiver.
- Returns: The interval between the receiver and the `another` parameter. If the receiver is earlier than `anotherDate`, the return value is negative. If `anotherDate` is `nil`, the results are undefined.
- SeeAlso: `timeIntervalSince1970`
- SeeAlso: `timeIntervalSinceNow`
- SeeAlso: `timeIntervalSinceReferenceDate`
*/
public func timeIntervalSince(_ date: Date) -> TimeInterval
// .... more
/// Returns true if the two `Date` values represent the same point in time.
public static func ==(lhs: Date, rhs: Date) -> Bool
/// Returns true if the left hand `Date` is earlier in time than the right hand `Date`.
public static func <(lhs: Date, rhs: Date) -> Bool
/// Returns true if the left hand `Date` is later in time than the right hand `Date`.
public static func >(lhs: Date, rhs: Date) -> Bool
/// Returns a `Date` with a specified amount of time added to it.
public static func +(lhs: Date, rhs: TimeInterval) -> Date
/// Returns a `Date` with a specified amount of time subtracted from it.
public static func -(lhs: Date, rhs: TimeInterval) -> Date
// .... more
}
在Swift3中，Date是struct，它意味着它是value type。 NSDate是class，它是reference type。
// Swift3
let a = Date()
let b = a //< `b` will copy `a`.
// So, the addresses between `a` and `b` are different.
// `Date` is some kind different with `NSDate`.
extension NSDate {
// MARK: - Dates comparison
func isGreaterThanDate(dateToCompare: NSDate) -> Bool {
return self.compare(dateToCompare) == NSComparisonResult.OrderedDescending
}
func isLessThanDate(dateToCompare: NSDate) -> Bool {
return self.compare(dateToCompare) == NSComparisonResult.OrderedAscending
}
func equalToDate(dateToCompare: NSDate) -> Bool {
return self.compare(dateToCompare) == NSComparisonResult.OrderedSame
}
}
如果你想在swift 3上比较日期与粒度（同一天或同一天等）。
func compareDate(date1:NSDate, date2:NSDate, toUnitGranularity: NSCalendar.Unit) -> Bool {
let order = NSCalendar.current.compare(date1 as Date, to: date2 as Date, toGranularity: .day)
switch order {
case .orderedSame:
return true
default:
return false
}
}
对于其他日历比较，将.day更改为;
.year .day。.hour .minute .second
Swift已经实现Date比较，只需使用date1> date2等等。
/// Returns true if the two `Date` values represent the same point in time.
public static func ==(lhs: Date, rhs: Date) -> Bool
/// Returns true if the left hand `Date` is earlier in time than the right hand `Date`.
public static func <(lhs: Date, rhs: Date) -> Bool
/// Returns true if the left hand `Date` is later in time than the right hand `Date`.
public static func >(lhs: Date, rhs: Date) -> Bool
/// Returns a `Date` with a specified amount of time added to it.
public static func +(lhs: Date, rhs: TimeInterval) -> Date
/// Returns a `Date` with a specified amount of time subtracted from it.
public static func -(lhs: Date, rhs: TimeInterval) -> Date
/// Add a `TimeInterval` to a `Date`.
///
/// - warning: This only adjusts an absolute value. If you wish to add calendrical concepts like hours, days, months then you must use a `Calendar`. That will take into account complexities like daylight saving time, months with different numbers of days, and more.
public static func +=(lhs: inout Date, rhs: TimeInterval)
/// Subtract a `TimeInterval` from a `Date`.
///
/// - warning: This only adjusts an absolute value. If you wish to add calendrical concepts like hours, days, months then you must use a `Calendar`. That will take into account complexities like daylight saving time, months with different numbers of days, and more.
public static func -=(lhs: inout Date, rhs: TimeInterval)
在Swift 3中，Date是可比较的，所以我们可以直接比较日期
let date1 = Date()
let date2 = Date()
let isGreater = date1 > date2
print(isGreater)
let isEqual = date1 == date2
print(isEqual)
或者
let result = date1.compare(date2)
switch result {
case .OrderedAscending : print("date 1 is earlier than date 2")
case .OrderedDescending : print("date 1 is later than date 2")
case .OrderedSame : print("two dates are the same")
}
在Date上创建extension的更好方法
extension Date {
fun isGreater(than date: Date) -> Bool {
return self > date
}
func isSmaller(than date: Date) -> Bool {
return self < date
}
func isEqual(to date: Date) -> Bool {
return self == date
}
}
用法let isGreater = date1.isGreater(than: date2)