CODEWITHSUNDEEP
iphone
folium
folium

Reputation: 413

Compare dates - overlooking the hour part

I frequently use the NSDate compare method - but I want to consider two dates similar if they are equal in year, month, day. I have made a procesure called "cleanDate" to remove the hour part before I compare.

-(NSDate*)cleanDate:(NSDate*)date {
    NSCalendarUnit unitflags;
    NSDateComponents *component;  
    NSCalendar *calendar;
    calendar=[[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]autorelease];
    unitflags=NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit;
    component=[calendar components:unitflags fromDate:date];
    return [calendar dateFromComponents:component]; //Dato uten klokke    
}

But my dates come out as:

2011-10-28 22:00:00 and some dates as: 2011-10-28 23:00:00

I want the hour part to be similar, e.g. 00:00.

Whats wrong? Does it have something to do with daylight saving time? Other? Thanks.

Upvotes: 1

Views: 145

Answers (2)

folium
folium

Reputation: 413

Seems like this is a Time Zone issue... I thought NSLog would default to the local time zone - but it seems to default to GMT...

Date with GMT time zone is: Sat, 29 Oct 2011 22:00:00 GMT+00:00
Date with system time zone is: Sun, 30 Oct 2011 00:00:00 GMT+02:00
NSlog shows 2011-10-29 22:00:00 +0000

When using NSLog(@"NSlog shows %@",finalDate); it seems to print the GMT time... 
When using this code - I will get the local date in my time zone:

NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setDateFormat:@"EEE, d MMM yyyy HH:mm:ss z"];
[dateFormatter setTimeZone:[NSTimeZone systemTimeZone]];
NSString *dateString = [dateFormatter stringFromDate:myDate];
NSLog(@"Date with system time zone is: %@",dateString);

... so my original cleanDate actually seems to do what I want after all...

Upvotes: 0

aahsanali
aahsanali

Reputation: 3547

-(NSDate*)cleanDate:(NSDate*)date {

            NSDateComponents *comps = [[NSCalendar currentCalendar] 
                                           components:NSDayCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit 
                                           fromDate:date];
                [comps setHour:0];
                [comps setMinute:0];    
                [comps setSecond:[[NSTimeZone systemTimeZone] secondsFromGMT]];

            return [[NSCalendar currentCalendar] dateFromComponents:comps];
}

Upvotes: 2

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