Combine a literal with an optional string

Question

What is the right way to implement this? preferably in one line.

var name: String?
...
let username = "@" + name

Note: it usernamemust be String?I do not want to deploy namefor concatenation.

Edit: if name- nil, usernameshould also be nil.

Answer 1

You can use the method map Optional:

let username = name.map { "@" + $0 }

If name- nil, then the closure is not performed, but the result nil. Otherwise, the closure is evaluated using the $0set to the expanded name.

Answer 2

Try it:

let username = name.flatMap { "@\($0)" }

Answer 3

EDITED :

. :

var name: String?
var username: String?

if let name = name {
  username = "@" + name
} 

Answer 4

The easiest and most readable option is likely to use if let, but you can also determine the method prependa String, the opposite String.append, and then use an optional chain:

extension String {
    func prepending(prefix: String) -> String {
        return prefix + self
    }
}

var name: String?
let username = name?.prepending("@")