Sorted Array選擇最大和最小的對象

Question

NSSortDescriptor* sortOrder = [NSSortDescriptor sortDescriptorWithKey: @"self" ascending: NO]; 
NSLog(@"%@",[ratio sortedArrayUsingDescriptors: [NSArray arrayWithObject: sortOrder]]); 

我排序的數組，但不能從數組中選擇最大和最小的對象。我怎樣才能做到這一點？

NSLog屏幕如下所示; 99, 99, 99, 91, 91, 88, 88, 88, 88, 77, 77, 66, 66, 66,

我怎樣才能採取objectforkey:0在有序陣列

Answer 1

你試過[array objectAtIndex:0]和[array lastObject]？你應該通過它們的索引訪問數組的元素，而不是objectForKey:。

id first = [array objectAtIndex:0]; 
id last = [array lastObject]; 

Answer 2

NSArray *sortedArray = [ratio sortedArrayUsingDescriptors: [NSArray arrayWithObject: sortOrder]]; 
NSLog(@"Biggest : %@", [sortedArray objectAtIndex:0]); 
NSLog(@"Smallest : %@", [sortedArray lastObject]);