Swift 3 - Comparing Date objects

Question

I\'m updating my app to Swift 3.0 syntax (I know it\'s still in beta but I want to be prepared as soon as it released).

Until the previous Beta of Xcode (Beta 5) I wa

Answer 1

Swift 5:

1) If you use Date type:

let firstDate  = Date()
let secondDate = Date()

print(firstDate > secondDate)  
print(firstDate < secondDate)
print(firstDate == secondDate)

2) If you use String type:

let firstStringDate  = "2019-05-22T09:56:00.1111111"
let secondStringDate = "2019-05-22T09:56:00.2222222"

print(firstStringDate > secondStringDate)  // false
print(firstStringDate < secondStringDate)  // true
print(firstStringDate == secondStringDate) // false 

I'm not sure or the second option works at 100%. But how much would I not change the values of firstStringDate and secondStringDate the result was correct.

Answer 2

Another way to do it:

    switch date1.compare(date2) {
        case .orderedAscending:
            break

        case .orderedDescending:
            break;

        case .orderedSame:
            break
    }

Answer 3

extension Date {
 func isBetween(_ date1: Date, and date2: Date) -> Bool {
    return (min(date1, date2) ... max(date1, date2)).contains(self)
  }
}

let resultArray = dateArray.filter { $0.dateObj!.isBetween(startDate, and: endDate) }

Answer 4

If you want to ignore seconds for example you can use

func isDate(Date, equalTo: Date, toUnitGranularity: NSCalendar.Unit) -> Bool

Example compare if it's the same day:

Calendar.current.isDate(date1, equalTo: date2, toGranularity: .day)

Answer 5

Date is Comparable & Equatable (as of Swift 3)

This answer complements @Ankit Thakur's answer.

Since Swift 3 the Date struct (based on the underlying NSDate class) adopts the Comparable and Equatable protocols.

• Comparable requires that Date implement the operators: <, <=, >, >=.
• Equatable requires that Date implement the == operator.
• Equatable allows Date to use the default implementation of the != operator (which is the inverse of the Equatable == operator implementation).

The following sample code exercises these comparison operators and confirms which comparisons are true with print statements.

Comparison function

import Foundation

func describeComparison(date1: Date, date2: Date) -> String {

    var descriptionArray: [String] = []

    if date1 < date2 {
        descriptionArray.append("date1 < date2")
    }

    if date1 <= date2 {
        descriptionArray.append("date1 <= date2")
    }

    if date1 > date2 {
        descriptionArray.append("date1 > date2")
    }

    if date1 >= date2 {
        descriptionArray.append("date1 >= date2")
    }

    if date1 == date2 {
        descriptionArray.append("date1 == date2")
    }

    if date1 != date2 {
        descriptionArray.append("date1 != date2")
    }

    return descriptionArray.joined(separator: ",  ")
}

Sample Use

let now = Date()

describeComparison(date1: now, date2: now.addingTimeInterval(1))
// date1 < date2,  date1 <= date2,  date1 != date2

describeComparison(date1: now, date2: now.addingTimeInterval(-1))
// date1 > date2,  date1 >= date2,  date1 != date2

describeComparison(date1: now, date2: now)
// date1 <= date2,  date1 >= date2,  date1 == date2

Answer 6

in Swift 3,4 you should use "Compare". for example:

DateArray.sort { (($0)?.compare($1))! == .orderedDescending }