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 was able to compare two Date objects using the operands <, > and ==. But in the latest beta (Beta 6) this isn't working any more. Here are some screenshots:

As you can see in both screenshots, these are two Date objects. But I get the following error:

What am I doing wrong? The functions are still declared in the Date class:

static func >(Date, Date)

Returns true if the left hand Date is later in time than the right hand Date.

Is this just a Beta bug or am I doing something wrong?

Answer 1

I have tried this snippet (in Xcode 8 Beta 6), and it is working fine.

let date1 = Date() let date2 = Date().addingTimeInterval(100)  if date1 == date2 { ... } else if date1 > date2 { ... } else if date1 < date2 { ... } 

Answer 2

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