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iOS

Posted by Jeff Andersen
Jeff Andersen
1,947 Points

Difference between as, as! and as? when unwrapping an optional

I'm working through the Build a Playlist Browser with Swift project and have run into an issue.

Unlike what Pasan has implemented in his code, XCode is suggesting that I use as! in place of as when assigning the playlistDictionary values.

For example, Pasan implements:

title = playlistDictionary["title"] as String!

but my XCode is suggesting I use:

title = playlistDictionary["title"] as! String!

On top of this, when I make the corrections as suggested by XCode, I receive "Unknown class Playlist in Interface Builder file." in my console output.

1 Answer

Jeff Andersen
Jeff Andersen
1,947 Points
Jeff Andersen
Jeff Andersen
1,947 Points

Re: "Unknown class Playlist in Interface Builder file.", I opened the code version of the storyboard file and noticed that somehow there was customClass="Playlist" on one of the nodes. Removing it removed the error.

Though, I'm not sure how it got there which I would like to understand.

Kevin Gonzales
Kevin Gonzales
4,638 Points

so the video is a bit outdated and from the newer versions (what you have now, as well as everyone ) as = as! not sure about as?