如何在Cocoa中访问大型NSDictionary的特定子集？

NSArray *keys = @[@"key1", @"key2", @"key3"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(SELF.key IN %@)", keys];
NSArray *filteredArray = [dictionaryArray filteredArrayUsingPredicate:predicate];

NSArray *keys = @[@"key1", @"key2", @"key3"];
NSArray *filteredArray = [dictionaryArray valueForKeyPath:@"@distinctUnionOfObjects.self"];

NSArray *keys = @[@"key1", @"key2", @"key3"];
NSArray *filteredArray = [dictionaryArray objectsAtIndexes:[NSIndexSet indexSetWithIndexesInRange:NSMakeRange(0, dictionaryArray.count)]];

NSArray *keys = @[@"key1", @"key2", @"key3"];
NSMutableArray *filteredArray = [NSMutableArray array];
for (NSDictionary *dict in dictionaryArray) {
    if ([keys containsObject:dict[@"key"]]) {
        [filteredArray addObject:dict];
    }
}