NSArray of Dates sort

Question

Considera esta matriz. No tiene llaves, así que no estoy seguro de poder usar NSSortDescriptor. ¿Cuál sería el mejor método para clasificarlos?

(
    "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

Puedes usar sortedArrayUsingFunction:

Aquí hay un código de ejemplo.

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];
}

Hay un número de este tipo de métodos de clasificación en NSArray. Vale la pena mirar a aquellos para familiarizarse con ellos.

Answer 2

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