convert [Dictionary<String,Any?>] to [Dictionary<String,Any!>] ? swift 3

Question

I am trying to append [Dictionary<String,Any!>] to [Dictionary<String,Any?>]

but I keep getting this Error:

Cannot Convert value of Type [Dictionary] to expected argument type of [Dictionary]

Although I didn't get this compile error with swift2 .

Here is my code:

class A{

     var statistics = [Dictionary<String,Any!>]();

     func1(){


       let oldStatiscs = self.func2()
       //i am getting the error here.
       self.statistics.append(oldStatiscs)


    }

    func2 () -> [Dictionary<String,Any?>]{


   }

}

Why am I getting this error on swift3? Why don't I get this error with swift2? How can this problem be solved?

Thanks

Answer 1

First off, even if you change both arrays of dictionaries to [Dictionary<String,Any>] you still get a similar error. You are trying to append an array to an array. So you first need to change:

self.statistics.append(oldStatiscs)

to:

self.statistics.append(contentsOf: oldStatiscs)

But even with that change, you can't append an array of [Dictionary<String,Any?>] to an array of [Dictionary<String,Any!>].

The simplest solution is to change the [Dictionary<String,Any!>] array to an [Dictionary<String,Any?>] array.

Then you end up with the following working code:

class A {
    var statistics = [Dictionary<String,Any?>]();

    func f1() {
        let oldStatiscs = self.f2()
        statistics.append(contentsOf: oldStatiscs)
    }

    func f2() -> [Dictionary<String,Any?>] {
        return [["Hi":"There"]]
    }
}

Even better is to get rid of Any? and use Any.

class A {
    var statistics = [Dictionary<String,Any>]();

    func f1() {
        let oldStatiscs = self.f2()
        statistics.append(contentsOf: oldStatiscs)
    }

    func f2() -> [Dictionary<String,Any>] {
        return [["Hi":"There"]]
    }
}

You need to explain why you think you can't change Any? to Any.