CODEWITHSUNDEEP
iosarraysswiftuikit
cmyr
cmyr

Reputation: 2275

Best way to init an array of views in swift?

I'm writing a new subclass of UIView using swift. I want to have an array of views, and I want to instantiate them in the initial declaration, for clarity.

If this was an Int array, I could do something like this:

let values: [Int] = (0...4).map() { $0 }

and so I'm trying to come up with some sort of similarly swifty one-liner that will create an array of UIButtons, instead of Ints.

my first thought was (0...4).map() { UIButton.buttonWithType(.Custom) } but if I do this (or if I replace the UIButton code with, say NSObject()) I get an error saying that "'Transition' does not have a member named 'map'". I can, say, do map() { "\($0)" } and get an array of strings.

My next thought was just to get an array of ints first, and then use map on those to return buttons, like:

let values: [UIButton] = (0...4)
    .map() { $0 }
    .map() { UIButton.buttonWithType(.Custom) }

but this gives me the same error. What am I doing wrong, here?

Upvotes: 2

Views: 2175

Answers (1)

cmyr
cmyr

Reputation: 2275

Okay, the solution came to me pretty quickly: I guess I can't quietly ignore the variable of the closure I'm passing in to the map function; I need to ignore it explicitly. So to get my array of 4 buttons, I can use an _ in the map function, like this:

var buttons = (0...4).map() {_ in UIButton.buttonWithType(.Custom) }

or what I actually ended up using:

lazy var buttons: [UIButton] = (0...4).map() { _ in
    let button = UIButton.buttonWithType(.Custom) as UIButton
    self.addSubview(button)
    return button
}

Upvotes: 4

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