减go 用SWIFT struct 填充的NSCountedSet

我有两个NSCountedSets，需要减go 它们.为了清晰起见，我使用一个简单的 struct ，其中一个属性作为对象:

struct MyStruct {
    let name: String
    
    init(_ name: String) {
        self.name = name
    }
}

func subtract(_ set1: NSCountedSet, _ set2: NSCountedSet) -> NSCountedSet {
    var result = NSCountedSet()

    for e in set1 {
        let count1 = set1.count(for: e)
        let count2 = set2.count(for: e)
        let newCount = count1 - count2

        if newCount > 0 {
            for _ in 1 ... newCount {
                result.add(e)
            }
        }
    }

    return result
}

let set1 = NSCountedSet(array: [MyStruct("A"), MyStruct("A"), MyStruct("A"), MyStruct("B"), MyStruct("C"), MyStruct("C")])
let set2 = NSCountedSet(array: [MyStruct("A"), MyStruct("B"), MyStruct("C")])

let set3 = subtract(set1, set2) // expected result: ["A", "A", "C"]`

print(set3.count(for: MyStruct("A"))) // observed result: 0 (expected 2)
print(set3.count(for: MyStruct("B"))) // observed result: 0 (expected 0)
print(set3.count(for: MyStruct("C"))) // observed result: 0 (expected 1)

但是，如果我使用:

let set1 = NSCountedSet(array: ["A", "A", "A", "B", "C", "C"])
let set2 = NSCountedSet(array: ["A", "B", "C"])

我得到了预期的结果.

我怀疑每MyStruct("A")个ETC实际上并不等于其他的ETC，因为它们是重新创建的.这就是我在添加print语句时看到的，count1始终为1,count2始终为0

所以也许有一种方法，我可以通过判断name的属性来计算MyStruct的数量，这可能吗？

如果没有，有没有其他解决办法？