How to sort the Array that contains date in strings in descending order? [duplicate]

Answer 1

You have to build yourself a suitable comparator:

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
NSLocale *enUSPOSIXLocale = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"];
[formatter setLocale:enUSPOSIXLocale];
[formatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
[formatter setDateFormat:@"MM/dd/yyyy"];

NSComparator myDateComparator = ^NSComparisonResult(id obj1,
                                                    id obj2) {
    NSDate *date1 = [formatter dateFromString:obj1];
    NSDate *date2 = [formatter dateFromString:obj2];

    return [date2 compare:date1]; // sort in descending order
};

then simply sort the array by doing:

NSArray *dateArray = @[@"01/12/2012", @"01/26/2011", @"02/09/2005",
                       @"02/24/2006", @"03/19/2007", @"07/14/2011",
                       @"08/17/2007", @"10/04/2007", @"10/31/2006",
                       @"12/05/2012", @"12/06/2006", @"12/23/2008"];

NSArray *sortedArray = [dateArray sortedArrayUsingComparator:myDateComparator];

NSLog(@"Sorted array is %@", sortedArray);

This sorts the strings (and not any modified array). You could also use string manipulation and convert m/d/y to y-m-d, but i guess for small data sets this approach would be fine.