如何获取存在于所有 NSArray 中的对象

Question

我有多个数组，例如：

NSArray *a = @[@"a", @"b", @"c"];
NSArray *b = @[@"d", @"a", @"e"];
NSArray *c = @[@"i", @"f", @"a"];

如你所见，"a"存在于数组a、b、c中。我想在提供的数组中创建一个 return 相同对象的函数。所以，就像这个一样，我想从他们那里得到这个 "a"。如果所有数组都没有相同的对象，则 return nil。例如"f"只存在于c中，所以函数应该return nil.

Answer 1

NSMutableSet *set = [NSMutableSet new];
NSMutableSet *set1 = [NSMutableSet setWithArray:a];
NSMutableSet *set2 = [NSMutableSet setWithArray:b];
NSMutableSet *set3 = [NSMutableSet setWithArray:c];


set = [set1 intersectSet:set2];
set = [set intersectSet:set3];

NSArray *allArray = [set allObjects];

Answer 2

NSMutableSet *intersection = [NSMutableSet setWithArray:a];
[intersection intersectSet:[NSSet setWithArray:b]];
[intersection intersectSet:[NSSet setWithArray:c]];

NSArray *intersecArray = [intersection allObjects];

这项工作！从你的代码中它 return a in result array

Answer 3

- (void)viewDidLoad
{
    [super viewDidLoad];
    NSArray *a = @[@"a", @"b", @"c"];
    NSArray *b = @[@"d", @"a", @"e"];
    NSArray *c = @[@"i", @"f", @"a"];

    NSArray *arraydOfAll=[NSArray arrayWithObjects:a,b,c,nil];
    NSArray *commonObjArray=[self intersectArray:arraydOfAll];
}



-(NSArray *)intersectArray:(NSArray *)allArray{
  NSMutableSet *set1 = [NSSet setWithArray:[allArray objectAtIndex:0]];
  for (NSInteger i=1;i<allArray.count : i++){
        [set1 intersectSet:[NSSet setWithArray:[allArray objectAtIndex:i]];
  }
  return  [set1 allObjects]
}

如何获取存在于所有 NSArray 中的对象

How to get the object that existed in all NSArray

objective-c

nsarray

ios