NSDateFormatter: dateFromString returns nil

Question

I have the date in the following format:

    NSString *dateString = @"1996-08-09T07:00:00Z";

I need to extract only the year from the date above:

    NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
    [dateFormat setTimeZone:[NSTimeZone systemTimeZone]];
    [dateFormat setLocale:[NSLocale currentLocale]];
    [dateFormat setDateFormat:@"yyyy"];
    [dateFormat setFormatterBehavior:NSDateFormatterBehaviorDefault];
    NSDate *date = [dateFormat dateFromString:dateString];
    NSLog(@"date : %@", date);

Log:

    2016-02-15 06:36:47.496 App[46714:5560483] date : (null)

I even tried:

    [dateFormat setLocale:[[[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"]

but no avail.

`dateFormat` set to `NSDateFormatter` clearly doesn't match the format of `dateString` — Larme, Apr 15 '16 at 13:44
this may help : http://stackoverflow.com/questions/19300032/nsdateformatter-datefromstring-always-returns-nil — Teja Nandamuri, Apr 15 '16 at 14:05

Anbu.Karthik · Accepted Answer · 2016-04-15T13:49:10.217

1

set date format as

                            1996-08-09T07:00:00Z
[dateFormat setDateFormat:@"yyyy-MM-dd'T'HH:mm:ssZ"];

update

    NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setTimeZone:[NSTimeZone systemTimeZone]];
[dateFormat setLocale:[NSLocale currentLocale]];
[dateFormat setDateFormat:@"yyyy-MM-dd'T'HH:mm:ssZ"];
[dateFormat setFormatterBehavior:NSDateFormatterBehaviorDefault];
NSDate *date = [dateFormat dateFromString:@"1996-08-09T07:00:00Z"];
NSLog(@"date : %@", date);
[dateFormat setDateFormat:@"yyyy"];
NSString *finalStr = [dateFormat stringFromDate:date];
NSLog(@"finalStr : %@", finalStr);

output

edited Apr 15 '16 at 13:49

answered Apr 15 '16 at 13:42

Anbu.Karthik

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check the updated answer – Anbu.Karthik Apr 15 '16 at 13:45
downvoters can explain whats wrong here – Anbu.Karthik Apr 15 '16 at 13:49
not sure who gave downvoted you - sorry. But i upvoted you so you dont get a hit. – user1107173 Apr 15 '16 at 14:12
@user1107173 -- its ok bro , in my answer is hopeful or not – Anbu.Karthik Apr 15 '16 at 14:12
@trojanfoe - not like that, we know about u , you are good in always – Anbu.Karthik Apr 15 '16 at 14:14
There is no reason to set the formatter's timezone to the system timezone. Let it default to the user's current timezone. Especially in a case like this where the timezone will be parsed from the date string. There is also no reason to set the formatter's locale to the current locale since that is also the default. – rmaddy Apr 15 '16 at 14:53

trojanfoe · Answer 2 · 2016-04-15T15:59:04.607

0

The format:

yyyy

does not match the date string:

1996-08-09T07:00:00Z

hence [NSDateFormatter dateFromString:] returned nil.

You want this format:

yyyy-MM-dd'T'HH:mm:ssZ

(Note the X specifier is documented as being the correct specifier for Z (Zulu Time) however during a discussion with @rmaddy, he has convinced me that Z is the correct one to use.)

and then to extract the year using NSDateComponents.

edited Apr 15 '16 at 15:59

answered Apr 15 '16 at 13:42

trojanfoe

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not sure who gave downvoted you - sorry. But i upvoted you so you dont get a hit. – user1107173 Apr 15 '16 at 14:11
Do not quote the `Z` in the date format. The `Z` in the date string represents the string's timezone. If you quote the `Z` in the date format, the formatter will ignore the `Z` and interpret the date string as local time instead of UTC time. – rmaddy Apr 15 '16 at 14:49
@rmaddy The unquoted `Z` specifier is not [documented](http://www.unicode.org/reports/tr35/tr35-31/tr35-dates.html#Date_Format_Patterns) to deal with an input character of `Z` (meaning *zulu time*). It supports -0800, GMT-8:00, -08:00 or -07:52:58 depending on how many `Z`s you specify. It looks like `X` does, however. – trojanfoe Apr 15 '16 at 14:56
I just ran a test to be 100% (I was only 99.5% sure before) and I am correct. The `Z` format specifier proper handles the `Z` timezone code as UTC time. – rmaddy Apr 15 '16 at 14:59
@rmaddy I am happy to accept that, however it's a bit annoying the documentation appears to be incorrect (or Apple's implementation). Anyway thanks for the correction. – trojanfoe Apr 15 '16 at 15:52

Suhas Arvind Patil · Answer 3 · 2016-04-15T13:49:24.577

Try this function:

 +(NSDate *)convertUTCDateLocal:(NSString*)inputString
{
    NSString *dateFormat = @"yyyy-MM-dd'T'HH:mm:sszz";
    //for input
    NSTimeZone *inputTimeZone =[NSTimeZone timeZoneWithName:@"UTC"];
    NSDateFormatter *inputDateFormatter = [[NSDateFormatter alloc] init];
    [inputDateFormatter setTimeZone:inputTimeZone];

    //NSString *inputString = @"2015-07-31T14:00:00+0000";
    [inputDateFormatter setDateFormat:dateFormat];
    NSDate *date = [inputDateFormatter dateFromString:inputString];

    //for output
    NSDateFormatter *outputDateFormatter = [[NSDateFormatter alloc] init];
    [outputDateFormatter setTimeZone:[NSTimeZone systemTimeZone]];
    [outputDateFormatter setLocale:[NSLocale currentLocale]];
    [outputDateFormatter setDateFormat: @"yyyy"];

    NSString *outputString = [outputDateFormatter stringFromDate:date];

    NSDate *outputDate = [outputDateFormatter dateFromString:outputString];

    return outputDate;
}

does not provide the year. – user1107173 Apr 15 '16 at 13:46 — user1107173, Apr 15 '16 at 13:46
so you want only year from the input? – Suhas Arvind Patil Apr 15 '16 at 13:47 — Suhas Arvind Patil, Apr 15 '16 at 13:47

NSDateFormatter: dateFromString returns nil

3 Answers3