Question

I am given a date:

2012-10-11T23:14:00-04:00

I am using this format for NSDateFormatter to parse:

yyyy-MM-dd'T'HH:mm:ss-ZZ

But it returns nil

Answer 1

Your date format is wrong. If you have a colon in the string you’re converting, you must put 5 Z characters in the format string, that is the correct usage. Also, you’d never include the +/- as part of the format, since you’re not guaranteed to only have dates + or – GMT (at least not when you’re talking about a /format/).

So, the correct format string would be yyyy'-'MM'-'dd'T'HH':'mm':'ssZZZZZ:

NSDateFormatter* formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"yyyy'-'MM'-'dd'T'HH':'mm':'ssZZZZZ"];
NSDate* date = [formatter dateFromString:@"2012-10-11T23:14:00-04:00"];
NSLog(@"Date: %@", date); // This correctly logs Date: 2012-10-12 03:14:00 +0000

Only using two Z characters would be the RFC 822 format, and your date string would have to look like: 2012-10-11T23:14:00-0400 (i.e., no hour/minute separator on the time zone offset). The timezone in your example string is ISO-8601. For more information, see: http://www.unicode.org/reports/tr35/tr35-25.html#Date_Format_Patterns