How to compare two dates in Objective-C

Question

I have two dates: 2009-05-11 and the current date. I want to check whether the given date is the current date or not. How is this possible.

Answer 1

Here's the function from Naveed Rafi's answer converted to Swift if anyone else is looking for it:

func isSameDate(#date1: NSDate, date2: NSDate) -> Bool {
    let calendar = NSCalendar()
    let date1comp = calendar.components(.YearCalendarUnit | .MonthCalendarUnit | .DayCalendarUnit, fromDate: date1)
    let date2comp = calendar.components(.YearCalendarUnit | .MonthCalendarUnit | .DayCalendarUnit, fromDate: date2)
    return (date1comp.year == date2comp.year) && (date1comp.month == date2comp.month) && (date1comp.day == date2comp.day)
}

Answer 2

This category offers a neat way to compare NSDates:

#import <Foundation/Foundation.h>

@interface NSDate (Compare)

-(BOOL) isLaterThanOrEqualTo:(NSDate*)date;
-(BOOL) isEarlierThanOrEqualTo:(NSDate*)date;
-(BOOL) isLaterThan:(NSDate*)date;
-(BOOL) isEarlierThan:(NSDate*)date;
//- (BOOL)isEqualToDate:(NSDate *)date; already part of the NSDate API

@end

And the implementation:

#import "NSDate+Compare.h"

@implementation NSDate (Compare)

-(BOOL) isLaterThanOrEqualTo:(NSDate*)date {
    return !([self compare:date] == NSOrderedAscending);
}

-(BOOL) isEarlierThanOrEqualTo:(NSDate*)date {
    return !([self compare:date] == NSOrderedDescending);
}
-(BOOL) isLaterThan:(NSDate*)date {
    return ([self compare:date] == NSOrderedDescending);

}
-(BOOL) isEarlierThan:(NSDate*)date {
    return ([self compare:date] == NSOrderedAscending);
}

@end

Simple to use:

if([aDateYouWantToCompare isEarlierThanOrEqualTo:[NSDate date]]) // [NSDate date] is now
{
    // do your thing ...
}

Answer 3

NSDate *today = [NSDate date]; // it will give you current date
NSDate *newDate = [NSDate dateWithString:@"xxxxxx"]; // your date 

NSComparisonResult result; 
//has three possible values: NSOrderedSame,NSOrderedDescending, NSOrderedAscending

result = [today compare:newDate]; // comparing two dates

if(result==NSOrderedAscending)
    NSLog(@"today is less");
else if(result==NSOrderedDescending)
    NSLog(@"newDate is less");
else
    NSLog(@"Both dates are same");

There are other ways that you may use to compare an NSDate objects. Each of the methods will be more efficient at certain tasks. I have chosen the compare method because it will handle most of your basic date comparison needs.

Answer 4

Here's the Swift variant on Pascal's answer:

extension NSDate {

    func isLaterThanOrEqualTo(date:NSDate) -> Bool {
        return !(self.compare(date) == NSComparisonResult.OrderedAscending)
    }

    func isEarlierThanOrEqualTo(date:NSDate) -> Bool {
        return !(self.compare(date) == NSComparisonResult.OrderedDescending)
    }

    func isLaterThan(date:NSDate) -> Bool {
        return (self.compare(date) == NSComparisonResult.OrderedDescending)
    }

    func isEarlierThan(date:NSDate) -> Bool {
        return (self.compare(date) == NSComparisonResult.OrderedAscending)
    }
}

Which can be used as:

self.expireDate.isEarlierThanOrEqualTo(NSDate())

Answer 5

What you really need is to compare two objects of the same kind.

1. Create an NSDate out of your string date (@"2009-05-11") :
   http://blog.evandavey.com/2008/12/how-to-convert-a-string-to-nsdate.html

2. If the current date is a string too, make it an NSDate. If its already an NSDate, leave it.

Answer 6

If you make both dates NSDates you can use NSDate's compare: method:

NSComparisonResult result = [Date2 compare:Date1];

if(result==NSOrderedAscending)
    NSLog(@"Date1 is in the future");
else if(result==NSOrderedDescending)
    NSLog(@"Date1 is in the past");
else
    NSLog(@"Both dates are the same");

You can take a look at the docs here.