NSArray of Dates sort

Question

Consider this array. It has no keys, so I am not sure I can use NSSortDescriptor. What would be the best method to sort them?

(
    \"Thursday, July 30, 2009\"         


        

Answer 1

You can use sortedArrayUsingFunction:

Here's some example code.

NSInteger dateSort(id s1, id s2, void *context)
{
    NSDateFormatter* format = (NSDateFormatter*)context;
    NSDate* d1 = [format dateFromString:s1];
    NSDate* d2 = [format dateFromString:s2];

    return [d1 compare:d2];
}

...

-(void)someObjectiveCMethod
{
    NSDateFormatter* format = [[[NSDateFormatter alloc] init] autorelease];

    // Find theses format codes here:
    // http://unicode.org/reports/tr35/tr35-6.html#Date_Format_Patterns
    //
    [format setDateFormat:@"EEEE, MMMM dd, yyyy"];

    NSArray* myArray = getMyArray();
    NSArray* sortedArray = [myArray sortedArrayUsingFunction:dateSort context:format];
}

There are a number of these sorts of sort methods in NSArray. It's worth looking at those to familiarize yourself with them.

Answer 2

NSArray * unsortedDates = ...;
NSArray * sortedDates = [unsortedDates sortedArrayUsingSelector:@selector(compare:)];