Simple swift array append not working

Question

I know this is going to be super elementary, but I have this piece of code:

var labels: [String]?

func initVC(image: Images){
    self.image = image

    let tempLabels = image.label?.allObjects as! [Labels]
    for i in 0..<tempLabels.count{
        labels?.append(tempLabels[i].label!)
    }

}

labels is in the public scope, so the function should have access to it, but when the loop runs through, labels is still nil with no elements.

When I po during debugging, tempLabels is as I expect it to be with 2 string elements.

I'm pretty sure this is a very simple problem, but I guess I'm just out of it right now.

Sam · Accepted Answer · 2016-06-24 00:49:47Z

37

Labels has never been initialised. Change

var labels:[String]?

to

var labels:[String] = []

answered Jun 24, 2016 at 0:49

Sam

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1 Comment

Octavio Antonio Cedeño Over a year ago

it's always the littlest things that are so time consuming. thanks again!

GJZ · Accepted Answer · 2016-06-24 01:03:01Z

3

You are declaring the labels variable but never allowing it to store information. This means that it does not necessarily exist, since it is not initialized, and therefore cannot be used.

For it to be useable, you must initialize it

var labels:[String] = []

edited Jun 24, 2016 at 1:03

answered Jun 24, 2016 at 0:52

GJZ

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1 Comment

Sam Over a year ago

Careful with your language, because this is not technically correct. The labels variable is actually never created and that is where the issue in this question first arrises. He has declared labels as an optional variable, meaning it may or may not be created at the point of use. The variable itself doesn't actually exist until it is initialised, until then it is just a declaration

Latcie · Accepted Answer · 2016-06-24 00:51:32Z

-7

Yep, it was super simple.

Changed

var labels: [String]?

To

var labels = [String]()

answered Jun 24, 2016 at 0:51

Latcie

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1 Comment

GJZ Over a year ago

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