Handling try and throws in Swift 3

Question

Before Swift 3 I was using:

guard let data = Data(contentsOf: url) else {                 print("There was an error!)                 return             } 

However I now have to use do, try and catch. I'm not familiar with this syntax. How would I replicate this behaviour?

Answer 1

The difference here is that Data(contentsOf: url) does not return an Optional anymore, it throws.

So you can use it in Do-Catch but without guard:

do {     let data = try Data(contentsOf: url)     // do something with data     // if the call fails, the catch block is executed } catch {     print(error.localizedDescription) } 

Note that you could still use guard with try? instead of try but then the possible error message is ignored. In this case, you don't need a Do-Catch block:

guard let data = try? Data(contentsOf: url) else {     print("There was an error!")     // return or break } // do something with data