Ordinamento NSArray of Dates

Question

Considera questo array. Non ha chiavi, quindi non sono sicuro di poter usare NSSortDescriptor. Quale sarebbe il metodo migliore per ordinarli?

(
    "Thursday, July 30, 2009",
    "Monday, September 07, 2009",
    "Wednesday, September 09, 2009",
    "Friday, August 14, 2009",
    "Saturday, September 05, 2009",
    "Monday, August 10, 2009",
    "Thursday, July 23, 2009",
    "Monday, October 12, 2009",
    "Friday, October 16, 2009",
    "Monday, August 17, 2009",
    "Tuesday, October 13, 2009",
    "Wednesday, September 30, 2009",
    "Sunday, August 16, 2009",
    "Thursday, August 27, 2009",
    "Monday, August 31, 2009",
    "Saturday, August 15, 2009",
    "Thursday, August 06, 2009",
    "Saturday, September 26, 2009",
    "Tuesday, September 29, 2009",
    "Tuesday, September 15, 2009",
    "Tuesday, September 01, 2009"
)

Answer 1

Puoi usare sortedArrayUsingFunction:

Ecco un esempio di codice.

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];
}

Esistono numero di questi tipi di metodi di ordinamento in NSArray. Vale la pena guardare quelli per familiarizzare con loro.

Answer 2

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