Is there a difference between how following bits of code work?
let x: Int = 4
and
let x: Int
x = 4
2 Answers
This one:
let x: Int = 4
creates a non-optional variable x and initialises it to 4. x can be used without issue.
This one:
let x: Int
// Cannot do anything with x yet
x = 4
creates a non-optional variable x with no defined value. It cannot be used without first assigning it to a value, either directly (as in your example) or by the result of some other statement. If you do try and use it, you'll get a compile-time error.
Comments
The only difference is that on the first one you are declaring a variable and assigning it at the same time, and the second one you declare it first and then assign it.
But there is no mayor difference.
answered Oct 18, 2016 at 13:52
Mago Nicolas Palacios
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2 Comments
Joshua Nozzi
...no difference except that you're using two instructions vs. 1 by using the second style, which is marginally less efficient. Arguably, though, it makes your code less readable, which is an excellent argument against using the more verbose style.
Joshua Nozzi
Let's not split hairs. "No major difference" is not the same thing as a nuanced answer explaining what the minor differences actually are.
letconstant after its declaration, given that you cannot read it before initialising it. Why would "proper programming style" suggest making it avar?