iOS - 3-letter Timezone abbreviation for NSTimeZone - ios

Question

How can I get three letter abbreviations in iOS for a TimeZone
[NSTimeZone abbreviationDictionary] gives abbreviation as 3-letter code. For eg:
NSZT, PDT, EST etc.
However,
NSString * ss = [NSTimeZone timeZoneWithName:#"Pacific/Auckland"].abbreviation;
gives GMT+12.
Is there a way I can get NSZT/NZDT instead?

Answer 1

You can get a full standard localized name of timezone using below code
Objective c:
NSTimeZone* timeZone = [NSTimeZone timeZoneWithName:#"Pacific/Auckland"];
NSString* timeZoneName = [timeZone localizedName:NSTimeZoneNameStyleStandard
locale:[NSLocale currentLocale]];
NSLog(#"%#", timeZoneName);
Swift:
let timezone:TimeZone = TimeZone.init(identifier: "Pacific/Auckland") ?? TimeZone.current
print(timezone.localizedName(for: .generic, locale: .autoupdatingCurrent))
print(timezone.localizedName(for: .standard, locale: .autoupdatingCurrent))
Output:
Objective c:
New Zealand Standard Time
Swift:
Optional("New Zealand Standard Time")
Optional("New Zealand Standard Time")
I think now you can get NZST from New Zealand Standard Time by splitting and combining string
Objective c:
NSMutableString * firstCharacters = [NSMutableString string];
NSArray *wordsArray = [timeZoneName componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
for (NSString * word in wordsArray){
if ([word length] > 0){
NSString * firstLetter = [word substringToIndex:1];
[firstCharacters appendString:[firstLetter uppercaseString]];
}
}
NSLog(#"%#", firstCharacters);
Swift:
let fullName = timezone.localizedName(for: .standard, locale: .autoupdatingCurrent) ?? ""
var result = ""
fullName.enumerateSubstrings(in: fullName.startIndex..<fullName.endIndex, options: .byWords) { (substring, _, _, _) in
if let substring = substring { result += substring.prefix(1) }
}
print(result)
Output:
NZST

Answer 2

As mentioned in the comment by rmaddy abbreviationDictionary only has 51 entries, but if you use only names from the abbreviationDictionary you can use following code:
NSDictionary *dict = [NSTimeZone abbreviationDictionary];
NSArray *abbreviations = [dict allKeysForObject:#"Pacific/Auckland"];
if (abbreviations.count > 0) {
NSLog(#"%#", abbreviations.firstObject);
}