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iOS Build a Playlist Browser with Swift Building the Music Library and Playlist Models Using a Playlist Instance

why I have to use as! instead of as in swift


I don't know if its a new rule in swift but my xcode always make me change as for as! when casting. I just click on fix-it otherwise won't run my app. It says that is necessary to downcast the value. Why in the videos appear like "as" and I have to use as!


Kevin Gonzales
Kevin Gonzales
4,638 Points

as is now as! since they updated it. hope that helped! I was confused too.

1 Answer

Kevin D
Kevin D
8,646 Points

I'm having the same issue. Xcode is telling me to change 'as' to 'as!' and my code doesn't run because of this.

Any ideas?

This is the code:

init(index: Int) {
    let musicLibrary = MusicLibrary().library
    let playlistDictionary = musicLibrary[index]

    title = playlistDictionary["title"] as String! // <-- these 'as' sections are causing a problem //
    description = playlistDictionary["description"] as String! // <-- //

    let iconName = playlistDictionary["icon"] as String! // <-- //
    icon = UIImage(named: iconName)

    let largeIconName = playlistDictionary["largeIcone"] as String! // <-- //
    largeIcon = UIImage(named: largeIconName)

    artists += playlistDictionary["artists"] as [String] // <-- //

    let colorsDictionary = playlistDictionary["backgroundColor"] as [String:CGFloat] // <-- //
    backgroundColor = rgbColorFromDictionary(colorsDictionary)


error message: "fatal error: unexpectedly found nil while unwrapping an Optional value"


Just realised I misspelled "largeIcon" in line 11. fixed it now!

Kevin Gonzales
Kevin Gonzales
4,638 Points

as is now as! since they updated it