如何知道新元素是否添加到 NSArray

Question

我有一个巨大的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"]。

如何知道两个元素的相加是海量的？在示例中，添加的新元素为 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元素并显示新元素。

你可以用NSMutableArray

的removeOjbectsInArray方法试试

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];

如何知道新元素是否添加到 NSArray

How to know if new element added to NSArray

objective-c

nsarray

输出