Comparing NSDates without time component

Question

In a swift playground, I have been using

NSDate.date() 

But, this always appears with the time element appended. For my app I need to ignore the time element. Is this possible in Swift? How can it be done? Even if I could set the time element to be the same time on every date that would work too.

Also, I am trying to compare two dates and at the moment I am using the following code:

var earlierDate:NSDate = firstDate.earlierDate(secondDate)

Is this the only way or can I do this in a way that ignores the time element? For instance I don't want a result if they are the same day, but different times.

Solution 1

Use this Calendar function to compare dates in iOS 8.0+

func compare(_ date1: Date, to date2: Date, toGranularity component: Calendar.Component) -> ComparisonResult

passing .day as the unit

Use this function as follows:

let now = Date()
// "Sep 23, 2015, 10:26 AM"
let olderDate = Date(timeIntervalSinceNow: -10000)
// "Sep 23, 2015, 7:40 AM"

var order = Calendar.current.compare(now, to: olderDate, toGranularity: .hour)

switch order {
case .orderedDescending:
    print("DESCENDING")
case .orderedAscending:
    print("ASCENDING")
case .orderedSame:
    print("SAME")
}

// Compare to hour: DESCENDING

var order = Calendar.current.compare(now, to: olderDate, toGranularity: .day)


switch order {
case .orderedDescending:
    print("DESCENDING")
case .orderedAscending:
    print("ASCENDING")
case .orderedSame:
    print("SAME")
}

// Compare to day: SAME

Solution 2

There are several useful methods in NSCalendar in iOS 8.0+:

startOfDayForDate, isDateInToday, isDateInYesterday, isDateInTomorrow

And even to compare days:

func isDate(date1: NSDate!, inSameDayAsDate date2: NSDate!) -> Bool

To ignore the time element you can use this:

var toDay = Calendar.current.startOfDay(for: Date())

But, if you have to support also iOS 7, you can always write an extension

extension NSCalendar {
    func myStartOfDayForDate(date: NSDate!) -> NSDate!
    {
        let systemVersion:NSString = UIDevice.currentDevice().systemVersion
        if systemVersion.floatValue >= 8.0 {
            return self.startOfDayForDate(date)
        } else {
            return self.dateFromComponents(self.components(.CalendarUnitYear | .CalendarUnitMonth | .CalendarUnitDay, fromDate: date))
        }
    }
}

Solution 3

Xcode 11.2.1, Swift 5 & Above

Checks whether the date has same day component.

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

Adjust toGranularity as your need.

Solution 4

In Swift 4:

func compareDate(date1:Date, date2:Date) -> Bool {
    let order = NSCalendar.current.compare(date1, to: date2, toGranularity: .day)
    switch order {
    case .orderedSame:
        return true
    default:
        return false
    }
}

Solution 5

I wrote the following method to compare two dates by borrowing from Ashley Mills solution. It compares two dates and returns true if the two dates are the same (stripped of time).

func compareDate(date1:NSDate, date2:NSDate) -> Bool {
    let order = NSCalendar.currentCalendar().compareDate(date1, toDate: date2,
        toUnitGranularity: .Day)
    switch order {
    case .OrderedSame:
        return true
    default:
        return false
    }
}

And it is called like this:

if compareDate(today, date2: anotherDate) {
    // The two dates are on the same day.
}

View more solutions

Comments

[The Paramagnetic Croissant]

You don't want to "ignore" the time part of the object. It seems that you want to format the date as a string without the time part. You can do that using NSDateFormatter.

[agf119105]

Thanks, Could you answer the how as well?!?

[The Paramagnetic Croissant]

@agf119105 using Google, for instance.

[vikingosegundo]

It answers the question as it wording, isn't it?

[vikingosegundo]

ah, come on, string operations?

[agf119105]

The wording of the question: "Is this possible in Swift? How can it be done?" meaning what code is required? @user3477950 tried Google thanks, but no useful results for Swift ...

[agf119105]

this doesn't help as I know how to print a localised description without the time element. I want to ignore the time-element as I need to compare two dates without the time getting in the way

[Léo Natan]

@agf119105 In that case, use NSDateComponents.

[vikingosegundo]

is this from UIKit? I cannot find it in a Foundation project.

[Ashley Mills]

This is one of the new iOS 8.0 NSCalendar APIs. See NSCalendar.h in iOS 7.1 to iOS 8.0 API Differences

[vikingosegundo]

finally, I always missed it.

[agf119105]

Thanks Ashley, really appreciate this answer - as I am such a beginner, if you have time could you some me how to use this? @AshleyMills

[Yer00n]

Not quite. The NSDate type represents a point in time; it contains date elements and time elements. So your code compares two points in time as opposed to the intended calendar dates in the original question.

[Duncan C]

The new NSCalendar methods like compareDate:toDate:toUnitGranularity: look very cool, but they're not in the Xcode docs or the online docs either. Where did you learn about them?

[Duncan C]

Swift doesn't even let me command-click on the method name to find it in the framework headers. I had to command-click on NSCalendar and look in it's header to find the method definition.

[Ashley Mills]

I found them in the iOS 8.0 API diffs document - these are always worth a read, all kinds of goodies appear in there! developer.apple.com/library/ios/releasenotes/General/…

[the Reverend]

Whats is the __NSDate type and _NSCopyOnWriteCalendarWrapper ?

[Ashley Mills]

@theReverend that was a hangover from an old version of Swift. Updated for 2.0 - thanks!

[jaw]

I think the two comments, indicating the expected results are wrong. // Compare to day: DESCENDING should be SAME and vice versa.

[Ashley Mills]

This is an identical copy of @zs2020 answer from 18 months earlier

[Ângelo Polotto]

other logic operator, like <, >, >= and <=, works as well.