For Loop with Index to Functional

Question

Trying to simply my code below:

for (index, point) in enumerate(self.points){
        let pointButton = UIButton()
        pointButton.frame = point.bounds
        self.view.addSubview(pointButton)
    }

Is there a better way to accomplish this through .map .filter or .reduce ?

Answer 1

The index is not used at all, therefore you do not need enumerate():

for point in self.points { ... }

(You mentioned in a comment that the index is used somewhere else, but we can review only the code that is shown in your question.)

let pointButton = UIButton()
pointButton.frame = point.bounds

can be simplified to

let pointButton = UIButton(frame: point.bounds)

and then you could get rid of the intermediate variable:

for point in self.points {
    self.view.addSubview(UIButton(frame: point.bounds))
}

and this looks like the best solution in your case to me.

You could use map() for that purpose:

self.points.map {
    self.view.addSubview(UIButton(frame: $0.bounds))
}

But using map() for its side effects is frowned-upon, see for example Higher order function: “Cannot invoke 'map' with an argument list of type '((_) -> _)'”, where an explicit foreach method is offered as an alternative:

extension Array {
    func foreach(function: T -> ()) {
        for elem in self {
            function(elem)
        }
    }
}

which can be used as

self.points.foreach {
    self.view.addSubview(UIButton(frame: $0.bounds))
}