如何从另一个已排序的数组中获取索引数组?

//Create a mutable array of the indexes in the myArray (just a list from 0...n)

NSMutableArray *indexes = [[NSMutableArray alloc] init];

for (int i = 0; i < myArray.count; i++){
    [indexes addObject: [NSNumber numberWithInteger:i]];
}

//Create a dictionary with myArray as the objects and the indexes as the keys
NSDictionary *tempDictionary = [NSDictionary dictionaryWithObjects:myArray forKeys:indexes];

//Create an array of myArray's keys, in the order they would be in if they were sorted by the values 
NSArray *sorted = [tempDictionary keysSortedByValueUsingSelector: @selector(compare:)];

indexOfObject:

NSArray *sorted = [myArray sortedArrayUsingSelector: @selector(compare:)];
NSMutableArray *indices = [NSMutableArray array];
for (id object in myArray)
  [indices addObject: [NSNumber numberWithInteger: [sorted indexOfObject: object]]];

(我脑子里想不出来,希望这能奏效。)

你也可以使用下面的代码,希望对你有用,

    NSSortDescriptor *_lastDescriptor = [[NSSortDescriptor alloc] initWithKey:@"" ascending:YES];
NSArray *_lastArray = [NSArray arrayWithObject:_lastDescriptor];


firstCharacterArray = (NSMutableArray *)[[nameIndexesDictionary allKeys] sortedArrayUsingDescriptors:_lastArray];
//firstCharacterArray = (NSMutableArray *)[[nameIndexesDictionary allKeys] sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)];
for (NSString *eachlastIndex in firstCharacterArray)
{
    NSSortDescriptor *lastDescriptor = [[NSSortDescriptor alloc] initWithKey:@""
                                                                   ascending:YES];
    //selector:@selector(localizedCaseInsensitiveCompare:)] ;
    NSArray *descriptorslast = [NSArray arrayWithObject:lastDescriptor];
    [[nameIndexesDictionary objectForKey:eachlastIndex] sortUsingDescriptors:descriptorslast];
    [lastDescriptor release];
}