Why 'Z' is at the end of date while converting from UTC to BST?

Question

Tried to convert from UTC to BST (British summer time) using date format. But it's gives me 'Z' at the end of the date. It is working for from UTS to IST conversation.Below is my code.

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setLocale:[NSLocale currentLocale]];
    [dateFormatter setDateFormat:@"dd'-'MM'-'yyyy HH':'mm':'ss ZZZZZ"];
    NSMutableString *dateString = [NSMutableString stringWithFormat:@"%@", [dateFormatter stringFromDate:[NSDate date]]];
    NSLog(@"%@",dateString); // This prints 20-11-2019 12:49:02 Z

Can any one know why does this happen. Any issue with the code or need to change something?

Answer 1

Replace the ZZZZZ in your date format with xxxxx. The use of ZZZZZ will give -99:99 unless the user is in the GMT timezone in which case it simply gives Z. xxxxx will give -99:99 regardless the user's timezone.

You can see specific details in the Unicode specification.

For ZZZZZ it states:

-08:00
-07:52:58
The ISO8601 extended format with hours, minutes and optional seconds fields. The ISO8601 UTC indicator "Z" is used when local time offset is 0. This is equivalent to the "XXXXX" specifier.

For XXXXX it states:

-08:00
-07:52:58
Z
The ISO8601 extended format with hours, minutes and optional seconds fields. The ISO8601 UTC indicator "Z" is used when local time offset is 0. (The same as xxxxx, plus "Z".)

For xxxxx it states:

-08:00
-07:52:58
The ISO8601 extended format with hours, minutes and optional seconds fields. (The same as XXXXX, minus "Z".)