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Todd Valentine
771 PointsForced Unwrapping of Dictionary Items
Why did we force unwrap the Strings from the playlistDictionary and not the playlist["artists"] or playlist["backgroundColor"]?
for example:
let largeIconName = playlistDictionary["largeIcon"] as String!
let colorsDictionary = playlistDictionary["backgroundColor"] as [String: CGFloat]
Is there not the possibility that artists and backgroundColor might not exist in the playlistDictionary and will return nil?
2 Answers
Michael Psoinos
8,178 PointsThe properties "artists" and "backgroundColor" were not declared as optionals, while all the other properties were. If they aren't optionals, you don't unwrap them. The declarations were as follows:
struct Playlist {
var title: String?
var description: String?
var icon: UIImage?
var largeIcon: UIImage?
var artists: [String] = []
var backgroundColor: UIColor = UIColor.clearColor()
There's no question mark in the artists or backgroundColor declarations. They are both initialized in their declarations, so it is not possible for them to have nil values.
However, accessing values in a dictionary returns them as optionals. That's why the colors are unwrapped in the rgbColorFromDictionary method.
Jan Kaltoun
2,161 PointsThanks! Very helpful, I had the same question.
Michael Psoinos
8,178 PointsYou're welcome. Glad I could help.