How to compare two dates in iOS

Question

I want to compare two dates.This my code i wrote

NSDate *c_date=[NSDate date];

NSDate  *newDate = [c_date dateByAddingTimeInterval:300];

This code is not working?What i am missing?

The code in this question isn't even trying to do a comparison. — JeremyP, Nov 12 '13 at 13:50

score 3 · Answer 1 · answered Nov 12 '13 at 13:45

3

From NSDate, you can use

- (NSComparisonResult)compare:(NSDate *)anotherDate

answered Nov 12 '13 at 13:45

Geraud.ch

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if ([[NSDate date] isEqualToDate:newDate]){ NSLog(@"same"); } if ([[NSDate date] compare:newDate]==NSOrderedSame) { NSLog(@"same"); } But both codes are not working..What i am missing..Please help me? – Vipin K V Ias Nov 12 '13 at 13:46
2

You've added 300 in creating the second date, why would they be the same? – David Snabel-Caunt Nov 12 '13 at 13:49
1

Edit your question to make it easier to answer – Geraud.ch Nov 12 '13 at 13:49

score 0 · Answer 2 · answered Nov 12 '13 at 13:46

You can use

- (NSComparisonResult)compare:(NSDate *)other;

which will yield a

typedef NS_ENUM(NSInteger, NSComparisonResult) {NSOrderedAscending = -1L, NSOrderedSame, NSOrderedDescending};

in your example you're just creating two different NSDate objects with a known NSTimeInterval (300), so there is no comparison.

score 0 · Answer 3 · answered Nov 12 '13 at 13:47

Use [NSDate timeIntervalSince1970] which will return a simple double value that can be used for comparison just like any other.

NSDate *c_date=[NSDate date];
NSDate *newDate = [c_date dateByAddingTimeInterval:300];
NSTimeInterval c_ti = [c_date timeIntervalSince1970];
NSTimeInterval new_ti = [newDate timeIntervalSince1970];
if (c_ti < new_ti) {
    // c_date is before newDate
} else if (c_ti > new_ti) {
    // c_date is after newDate
} else {
    // c_date and newDate are the same
}

There are also the [NSDate compare:] method, that you might find more convenient.

score 0 · Answer 4 · edited May 23 '17 at 10:25

Here's the thing (well, it might be the thing, it's not completely 100% clear from your question). NSDate represents an interval in seconds since 1st January 1970. Internally, it uses a floating point number (a double in OS X, not sure in iOS). This means that comparing two NSDates for equality is dry hit and miss, actually it's mostly miss.

If you want to make sure one date is within, say, 1/2 a second of another date, try:

fabs([firstDate timeIntervalSinceDate: secondDate]) < 0.5

If you just want both dates to be on the same day, you'll need to muck about with NSCalendar and date components.

How to compare two dates in iOS

4 Answers4