NSMutableSet集减号集不工作

Question

我一定是错过了一些基本的东西--希望有人能向我指出这一点。

我有两个NSSets。集合A包含40个NSNumber值，而设置B包含20个NSNumber值。集合A包含所有的集合B的20个值加上20个其他值不被集合共享。

我想做的是: NSSet *newSet = Set A- Set B，其中新集只包含集合B中不包含的集合A中的20个值。尽管我使用的是'minusSet'，但我的新集合总是包含所有40个原始值。我已经记录了每个集合A和B的内容，以确保它们包含我前面描述的内容。

这是我的代码：

1)创建集合A(包含40 NSNumbers)

NSMutableSet *fetchedThreadIds = [NSMutableSet setWithArray:[threadedJsonMessages valueForKey:@"tid"]];

2)创建集合B(包含20 NSNumbers，也在集合A中)

NSSet *savedThreads = threadIdsForSavedThreads([fetchedThreadIds allObjects]);

3)试图从集合A中减去集合B：

[fetchedThreadIds minusSet:savedThreads];

4)将所有剩余的对象添加到新数组中：

threadIdsForMessageFetch = [fetchedThreadIds allObjects];

然而，threadIdsForMessageFetch包含40个对象，而不是20个。

集A

{(
2540000000136987400,
2540000000141777055,
2540000000144609986,
2540000000125243232,
2540000000144610000,
2320000003021796109,
2540000000144375484,
2540000000136185765,
2540000000135311778,
2540000000135311816,
2540000000124128112,
2540000000125012438,
2480000001401011569,
2540000000144610015,
2540000000135311744,
2540000000139755359,
2540000000135311848,
2540000000143846308,
2540000000145732667,
2540000000143985955,
2540000000136185740,
2540000000135756434,
2540000000134373148,
2540000000140816249,
2540000000130860748,
2540000000127140093,
2540000000143526120,
2540000000102176392,
2540000000144609962,
2540000000128826163,
2540000000136185694,
2540000000133208691,
2540000000144555891,
2540000000138091838,
2540000000130179358,
2540000000126098342,
2540000000145162237,
2540000000131688927,
2540000000136185715,
2540000000143526101
)}

集B

{(
2540000000136987400,
2540000000138091838,
2540000000143985955,
2540000000144555891,
2540000000140816249,
2540000000145732667,
2540000000144609986,
2540000000144610000,
2540000000144609962,
2540000000144610015,
2540000000141777055,
2540000000143526101,
2540000000143526120,
2480000001401011569,
2540000000136185694,
2540000000145162237,
2540000000143846308,
2320000003021796109,
2540000000144375484,
2540000000139755359
)}

新阵列：

<__NSArrayI 0xc4b8e40>(
2540000000136987400,
2540000000141777055,
2540000000144609986,
2540000000125243232,
2540000000144610000,
2320000003021796109,
2540000000144375484,
2540000000136185765,
2540000000135311778,
2540000000135311816,
2540000000124128112,
2540000000125012438,
2480000001401011569,
2540000000144610015,
2540000000135311744,
2540000000139755359,
2540000000135311848,
2540000000143846308,
2540000000145732667,
2540000000143985955,
2540000000136185740,
2540000000135756434,
2540000000134373148,
2540000000140816249,
2540000000130860748,
2540000000127140093,
2540000000143526120,
2540000000102176392,
2540000000144609962,
2540000000128826163,
2540000000136185694,
2540000000133208691,
2540000000144555891,
2540000000138091838,
2540000000130179358,
2540000000126098342,
2540000000145162237,
2540000000131688927,
2540000000136185715,
2540000000143526101
)

在减号集合调用之前，A和B的计数如下：

2014-05-14 22:37:00.900 App[35877:60b] fetchedThreadIdsCount = 40
2014-05-14 22:37:00.900 App[35877:60b] savedThreadsCount = 20

Answer 1

我尝试了这个方法，所以我猜还有其他的代码丢失了，或者NSNumbers真的不一样，只是打印出来的表示形式是一样的。

NSMutableSet *fetchedThreadIds = [NSMutableSet setWithObjects:@1, @2, @3, @4, nil];
NSSet *savedThreads = [NSSet setWithObjects:@2, @3, nil];
NSLog(@"fetchedThreadIds: %@", fetchedThreadIds);
NSLog(@"savedThreads: %@", savedThreads);

[fetchedThreadIds minusSet:savedThreads];
NSLog(@"fetchedThreadIds: %@", fetchedThreadIds);
NSArray *threadIdsForMessageFetch = [fetchedThreadIds allObjects];
NSLog(@"threadIdsForMessageFetch: %@", threadIdsForMessageFetch);

NSLog输出：

fetchedThreadIds：{( 3 . 2、 1、 4 )} savedThreads：{( 3 . (2 )} fetchedThreadIds：{( 1、 4 )} threadIdsForMessageFetch：( 1、 4)

张贴作为一个主要的格式的答案。