Getting null when trying to extract year value from a date [duplicate] - ios

Question

This question already has answers here:
NSDate from NSString gives null result
(3 answers)
Closed 9 years ago.
My code is the following:
NSString *dateString = #"1339007317";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"yyyy"];
NSDate *date = [dateFormatter dateFromString:dateString];
NSString *year = [dateFormatter stringFromDate:date];
NSLog(#"%#",year);//null
How to fix that? thanx.

Answer 1

It is because you are using unix timestamp and you can convert unix timestamp into year or any date format as :
//Posted Date Format
NSString *dateStr = #"1339007317";
NSDate *date = [NSDate dateWithTimeIntervalSince1970:[dateStr doubleValue]];
NSLocale *locale = [[NSLocale alloc] initWithLocaleIdentifier:#"en-US"];
NSDateFormatter *dateFormatter1 = [[NSDateFormatter alloc] init];
[dateFormatter1 setDateFormat:#"yyyy"]; //Here you can set any date format Ex:#"dd MMM, yyyy hh:mm a" or#"dd/MM/yyyyy" according to your requirement
[dateFormatter1 setLocale:locale];
[dateFormatter1 setTimeZone:[NSTimeZone systemTimeZone]];
dateStr = [dateFormatter1 stringFromDate: date];
Hope it helps you.

Answer 2

You need two date formats. The first should match the format of the string you wish to convert to an NSDate. The second format needs to represent the format you want. Use the 2nd to convert the NSDate to the new string.
Also, why do you create a date object then immediately replace it with a new one?
Change this:
NSDate *date = [[NSDate alloc] init];
date = [dateFormatter dateFromString:dateString];
to:
NSDate *date = [dateFormatter dateFromString:dateString];
Your code needs to be like this:
NSString *dateString = #"1339007317";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"???"]; // format that matches the dateString
NSDate *date = [dateFormatter dateFromString:dateString];
[dateFormatter setDateFormat:#"yyyy"]; // the desired new format
NSString *year = [dateFormatter stringFromDate:date];
NSLog(#"%#",year);