我可以在“ for in”控制结构中向下转换Swift吗？

Question

I have a sorted array of details generated from an NSSet. I want to iterate through them to print them out. Right now I do this:

    for aDetail in sortedDetails! {
        let someDetail = aDetail as! Detail
        if someDetail.parentDetail != "" {
            print("----\(someDetail.name)")
        } else {
            print("\(someDetail.name)")
        }
    }

Is there a cleaner way to do the "let someDetail = aDetail as! Detail" in the "for-in" definition instead? (ie Force the downcast in the definition of the for-in loop rather than create a separate variable that's cast?)

This works but it feels clunky.

Answer 1

If the array's contents are guaranteed to be convertible to Detail , you can cast the array:

for aDetail in sortedDetails as! [Detail] {
    if aDetail.parentDetail != "" {
        print("----\(aDetail.name)")
    } else {
        print("\(aDetail.name)")
    }
}