如何将NSMutableOrderedSet转换为通用数组? [英] How to covert NSMutableOrderedSet to generic array?

问题描述

我有这个for循环，p是NSManagedObject，fathers是to-many关系，所以我需要将NSMutableOrderedSet强制转换为[Family]，但是它不起作用，为什么?

I have this for loop, p is a NSManagedObject, fathers is a to-many relationship, so I need to cast NSMutableOrderedSet to [Family] but it does not work, why?

for f in p.fathers as [Family] {
}

推荐答案

您可以通过array属性获取集合的数组表示形式-然后可以将其向下转换为适当的类型并分配给变量:

You can obtain an array representation of the set via the array property - then you can downcast it to the proper type and assign to a variable:

let families = p.fathers.array as [Family]

但是当然您也可以在循环中直接使用它:

but of course you can also use it directly in the loop:

for f in p.fathers.array as [Family] {
    ....
}

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