- (void)viewDidLoad {
  [super viewDidLoad];
  // Do any additional setup after loading the view, typically from a nib.
  //直接排序对象
  NSSortDescriptor *descriptor = [NSSortDescriptor sortDescriptorWithKey:nil ascending:YES];
  NSArray *descriptors = [NSArray arrayWithObject:descriptor];
  NSArray *myDataArray = [NSArray arrayWithObjects:@"what", @"xero", @"highligth", @"mountain", @"Victory", @"Balance", nil];
  NSLog(@"---myDataArray---%@",myDataArray);
  NSArray *resultArray = [myDataArray sortedArrayUsingDescriptors:descriptors];
  NSLog(@"%@", resultArray);
  //NSArray 使用sortedArrayUsingDescriptors，返回排序好的数组。
  //NSMutableArray可以直接使用sortUsingDescriptors，对数组本身排序。
}

2015-10-23 11:56:45.178 对数组进行排序[6739:168615] (
  Balance,
  Victory,
  highligth,
  mountain,
  what,
  xero
)