NSDate returns different answers

Question

I'm grabbing the current date and comparing it to a predefined date, however I'm having an issue where the string is different sometimes. My code:

NSDate *todaysDate = [NSDate date];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
NSString *dateToday = [dateFormatter stringFromDate:todaysDate];
NSLog(@"%@", dateToday);

Sometimes I'll get 'Dec 30, 2013' - sometimes 'Dec 30 2013' (no comma) and sometimes '30 Dec 2013'. I cannot see why this would happen.

Any thoughts?

EDIT: Responding to questions asked. I'm simply trying to see if the current date is the same as a predefined date, or if it's beyond that date. My code for this is:

if ([dateToday  isEqual: @"30 Dec 2013"]) {
    //It's the day of the event, run the day view
    [self performSegueWithIdentifier:@"mainToDay" sender:self];
} else if ([todaysDate timeIntervalSinceDate:postEventDate] > 0) {
    //It's after the event, run the post event screen
    [self performSegueWithIdentifier:@"mainToPost" sender:self];
}

I was simply using the log to see what was returned then emulating it. I didn't realise it would change. :)

Cheers.

What form is your predefined date in? Comparing strings may not be the best approach. But if you do, you should at least use an explicit date format with an explicit locale to ensure consistent results. — rmaddy, Dec 30 '13 at 23:29
You will be better of using `NSDateComponents` to construct 2nd date - and compare `NSDate`s, not their string representation (you could also compare string representation if you use same fixed format for both dates). See http://stackoverflow.com/a/1563874/653513 — Rok Jarc, Dec 30 '13 at 23:55

coneybeare · Answer 1 · 2013-12-30T23:55:57.460

2

This can happen if the language or locale of the test device changes, but it should be consistent when there are no changes.

UPDATE

Check some of the functions in these libraries, makes you life a ton easier. I use Erica Saduns in my apps. She has a isEqualToDateIgnoringTime which seems exactly like what you are looking for.

edited Dec 30 '13 at 23:55

answered Dec 30 '13 at 23:03

coneybeare

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Ahh ok, so is there a more concrete way to do this? – Andrew Dec 30 '13 at 23:23

score 0 · Accepted Answer · answered Dec 31 '13 at 00:34

Using a date style will result in one of many possible strings based on the user's locale and language. There are better approaches. If you really want to compare against a hardcoded date string, at least do the following:

NSDate *todaysDate = [NSDate date];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd"];
NSString *dateToday = [dateFormatter stringFromDate:todaysDate];

if ([dateToday isEqualToString:@"2013-12-30"]) {
}

This ensures a consistent format and eliminates any language specific text.

NSDate returns different answers

2 Answers2