如何知道是否添加新元素NSArray

Question

我有一个庞大的array=["1","2","3","4","5","6"]，随着时间的推移。例如：array=["1","2","3","4","5","6","10","11"]。

如何知道两个元素添加到大量？在本例中，添加了新的元素是10和11

Answer 1

试试这个，

NSArray *array1 = @[@"1",@"2",@"3",@"4",@"5",@"6"]; 
NSArray *array2 = @[@"1",@"2",@"3",@"4",@"5",@"6",@"10",@"11"]; 
NSMutableArray *addedArray = [NSMutableArray array]; 

for(int i = 0; i < [array2 count]; i++) 
{ 
    if (![array1 containsObject:[array2 objectAtIndex:i]]) { 
     [addedArray addObject:[array2 objectAtIndex:i]]; 
    } 
} 

NSLog(@"New elements is added: %@", addedArray); 

输出：

New elements is added: 
(
10, 
11 
) 

Answer 2

所以基本上你只需要删除旧的元素，并显示新元素。

您可以通过使用NSMutableArray

i.e. 
NSArray *oldArray = @[@"1",@"2",@"3",@"4",@"5",@"6"]; 
NSArray *newArray = @[@"1",@"2",@"3",@"4",@"5",@"6",@"10",@"11"]; 
NSMutableArray *result = [newArray mutableCopy]; // make sure you make it a mutable copy 
// remove the existing elements 
[result removeObjectsInArray:oldArray]; 
NSLog(@"remaining entry: %@",result); 

输出

@[10,11];