Re: UserDefaults not letting me access a dictionary?
Re: UserDefaults not letting me access a dictionary?
- Subject: Re: UserDefaults not letting me access a dictionary?
- From: Alex Hall <email@hidden>
- Date: Mon, 16 Nov 2015 22:13:11 -0500
> On Nov 14, 2015, at 15:41, Quincey Morris <email@hidden> wrote:
>
> On Nov 14, 2015, at 10:18 , Alex Hall <email@hidden <mailto:email@hidden>> wrote:
>>
>> In a playground, accessing a dictionary of [String:Bool] works fine, as expected. In the app, though, I get an error that I can't index [String:Bool] with type 'String'. I don't understand why that is, so wanted to see if there was anything special about what UserDefaults returns. In the header file it's just an optional dictionary, and my 'if let' takes care of that. I'm not sure why else my code would error out right there, though. I haven't played much with user preferences before, so I may well be missing something, but it seems easy enough to use and there shouldn't be anything funny going on. Any thoughts? Thanks!
>
> You’ve got the types wrong. ‘dictionaryForKey’ returns type [String: AnyObject]?, which means — once you’ve stripped the optionality off it — that you’re trying to assign from AnyObject to Bool. The error message is confusing, because it seems to be saying that your key isn’t a string, but what it actually means is that a subscripting operator taking a String key and returning a Bool doesn’t exist in class [String: AnyObject], and that’s quite true.
Of course! I keep thinking Swift will figure out what I want AnyObject to be and cast for me, which is very obviously not true and not a good idea. Forcing a cast solved it, thanks. I'll definitely file this, as that's one of the worst error messages I've seen from Swift.
>
> You should probably file a bug report about the crappy error message. To fix your code you can do something like:
>
> someFilterSwitch.on = filter[someCategory.rawValue] as! Bool
>
> or downcast the dictionary itself to [String: Bool].
--
Have a great day,
Alex Hall
email@hidden
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