display.text = newValue != nil ? \"\\(newValue!)\" : \" \"
Does the syntax of the code mean, let display.text = newValue, if it does not equal nil
The answers about the ternary operator are correct.
An alternative way to write this would be with the "nil-coalescing operator" ??:
??
display.text = newValue ?? ""
Which means if the value before ?? Is not nil, use that unwrapped value, else use the value after ??