The following:
var emptyArray = [String]();
What do I need the parentheses () for? [String] says, that the array accepts strings only. But why do I have to put the () there?
1 Answer
Two things are true in Swift:
- To instantiate an object of type
Tin Swift you write codeT(). - The type "name" of an array of Strings is
[String]
Combine the two and you get [String]()
answered Sep 4, 2015 at 20:41
-
So:
var emptyArray = [String]();instantiates an object of the type emptyArray and emptyArray is a array of strings?PeterPan– PeterPan2015-09-04 20:47:45 +00:00Commented Sep 4, 2015 at 20:47 -
3@S.Eberl No, the type is "array of String". I've never written Swift, but I doubt it has a type "empty array". So you're creating an object of type "array of String" which happens to be empty. The emptiness itself isn't part of the type.Andres F.– Andres F.2015-09-04 21:20:29 +00:00Commented Sep 4, 2015 at 21:20
-
1Number 1 doesn't explain why that is, and number 2 doesn't elaborate much. Let me fill the holes:
T()is a shorthand forT.init().[String]is a shorthand forArray<String>. Thus,[String]()is a shorthand forArray<String>.init()Alexander– Alexander2016-08-08 21:34:19 +00:00Commented Aug 8, 2016 at 21:34
String. The round things afterward are parentheses, or just "parens" if you're being informal.[String]denotes a type: array of strings, but you're not trying to assign a type toemptyArray; you're trying to assign an instance of that type, which is where the parens come in. (Note: if any actual Swift devs see this and I'm way off, bear in mind the above: I've never used Swift. Just making an educated guess here.)