如何在objective-c中生成一個隨機日期？

Question

我想在兩個日期之間生成一個隨機日期 - 例如今天到現在60天之間的隨機日期。我怎麼做？

UPDATE

運用的答案信息，我想出了這個方法，這是我經常使用：

// Generate a random date sometime between now and n days before day. 
// Also, generate a random time to go with the day while we are at it. 
- (NSDate *) generateRandomDateWithinDaysBeforeToday:(NSInteger)days 
{ 
    int r1 = arc4random_uniform(days); 
    int r2 = arc4random_uniform(23); 
    int r3 = arc4random_uniform(59); 

    NSDate *today = [NSDate new]; 
    NSCalendar *gregorian = 
      [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]; 

    NSDateComponents *offsetComponents = [NSDateComponents new]; 
    [offsetComponents setDay:(r1*-1)]; 
    [offsetComponents setHour:r2]; 
    [offsetComponents setMinute:r3]; 

    NSDate *rndDate1 = [gregorian dateByAddingComponents:offsetComponents 
                toDate:today options:0]; 

    return rndDate1; 
} 

Answer 1

1. 產生一個隨機數1到60之間

   int r = arc4random_uniform(60) + 1; 
   
   // Usage : arc4random_uniform(hi - lo + 1) + lo 
   

2. 獲取當前da TE

   [NSDate date]; 
   

3. 使用NSDateComponents從您的days組件減去隨機數併產生一個新的日期。

Answer 2

獲取一個隨機數並將其用作時間間隔，然後將其添加到開始日期。例如。

NSTimeInterval timeBetweenDates = [endDate timeIntervalSinceDate:startDate]; 
NSTimeInterval randomInterval = ((NSTimeInterval)arc4random()/ARC4RANDOM_MAX) * timeBetweenDates; 

NSDate *randomDate = [startDate dateByAddingTimeInterval:randomInterval]; 

Answer 3

使用秒。僞代碼：

1 Generate a random integer between 0 and (60 * 60 * 24 * 60) 
2 Get the unixtime in seconds for the current time 
3 Add your random integer 
4 Convert this integer back to a date 

Answer 4

這裏框架在生成隨機日期方面做得很好。但是在斯威夫特： https://github.com/thellimist/SwiftRandom/blob/master/SwiftRandom/Randoms.swift

public extension NSDate { 
    /// SwiftRandom extension 
    public static func randomWithinDaysBeforeToday(days: Int) -> NSDate { 
     let today = NSDate() 

     guard let gregorian = NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian) else { 
      print("no calendar \"NSCalendarIdentifierGregorian\" found") 
      return today 
     } 

     let r1 = arc4random_uniform(UInt32(days)) 
     let r2 = arc4random_uniform(UInt32(23)) 
     let r3 = arc4random_uniform(UInt32(23)) 
     let r4 = arc4random_uniform(UInt32(23)) 

     let offsetComponents = NSDateComponents() 
     offsetComponents.day = Int(r1) * -1 
     offsetComponents.hour = Int(r2) 
     offsetComponents.minute = Int(r3) 
     offsetComponents.second = Int(r4) 

     guard let rndDate1 = gregorian.dateByAddingComponents(offsetComponents, toDate: today, options: []) else { 
      print("randoming failed") 
      return today 
     } 
     return rndDate1 
    } 

    /// SwiftRandom extension 
    public static func random() -> NSDate { 
     let randomTime = NSTimeInterval(arc4random_uniform(UInt32.max)) 
     return NSDate(timeIntervalSince1970: randomTime) 
    } 

} 

Answer 5

斯威夫特3.X +

public extension Date { 
    /// SwiftRandom extension 
    public static func randomWithinDaysBeforeToday(days: Int) -> Date { 
     let today = Date() 
     let gregorian = Calendar(identifier: .gregorian) 

     let r1 = arc4random_uniform(UInt32(days)) 
     let r2 = arc4random_uniform(UInt32(23)) 
     let r3 = arc4random_uniform(UInt32(23)) 
     let r4 = arc4random_uniform(UInt32(23)) 

     let offsetComponents = NSDateComponents() 
     offsetComponents.day = Int(r1) * -1 
     offsetComponents.hour = Int(r2) 
     offsetComponents.minute = Int(r3) 
     offsetComponents.second = Int(r4) 

     let rndDate1 = gregorian.date(byAdding: offsetComponents as DateComponents, to: today) 
     return rndDate1! 
    } 

    /// SwiftRandom extension 
    public static func random() -> Date { 
     let randomTime = TimeInterval(arc4random_uniform(UInt32.max)) 
     return Date(timeIntervalSince1970: randomTime) 
    } 
} 

_{附： Esqarrouth的answer更正了最新的Swift。}