Swift guard else called on dictionary key with NULL value

Question

If I have a Dictionary returned from a NSNotification containing the following

print(notificationObj.object)
Optional({
    age = "<null>";
    names =     (
        David
    );
})

Then the guard else is called when trying to assign this to a variable:

guard let categories = notificationObj.object as? [String:[String]] else {
  // Gets to here
  return
}

How can I handle the case where a Dictionary key is null.

Answer 1

Your dictionary does contain ...

Optional({
    age = "<null>";
    names =     (
        David
    );
})

... and ...

• age = ... is String = String (value is single String),
• names = ( ... ) is String = [String] (value is array of Strings).

You can't cast it to [String:[String]] because the first pair doesn't fit this type. This is the reason why your guard statement hits else.

Hard to answer your question. Dictionary contains names, you want categories, names key does contain David, which doesn't look like category, ... At least you know why guard hits else.