Covert NSString date to NSDate object and than sort array based on date
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setLocale:[[[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"] autorelease]];
[dateFormatter setDateFormat:@"YYYY-MM-dd HH:mm:ss ZZZ"];
NSDate *date = [dateFormatter dateFromString:dateStr];
NSComparisonResult dateSort(NSString *s1, NSString *s2, void *context) {
NSDate *d1 = [NSDate dateWithString:s1];
NSDate *d2 = [NSDate dateWithString:s2];
return [d1 compare:d2];
}
NSArray *sorted = [unsorted sortedArrayUsingFunction:dateSort context:nil];