Compilation errors when declaring arrays with nil default values

Question

i am encountering weird error messages i cannot make sense of when declaring arrays with nil declare values.

I am doing this in Xcode playground.

//this is ok
var threeDoubles = [Double](count: 3, repeatedValue: 0.0)

//error: incorrect argument label in call, have count expected "arrayLiteral"
var threeDoubles2 = [Double](count: 3)

//error: extra argument "repeatedValue" in call
var threeDoubles2 = [Double](count: 3, repeatedValue: nil)

meow · Accepted Answer · 2015-01-18 22:24:10Z

3

Ok, I found my own bug. Basically, the values cannot be nil because I declared the array as Double, and not Double?

It has nothing to do with an extra argument, which was what xcode was showing me.

var threeDoubles2 = [Double?](count: 3, repeatedValue: nil)

The arcane error messages can really throw you off course even for simple errors.

edited Jan 18, 2015 at 22:24

answered Jan 17, 2015 at 5:18

meow

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1 Comment

Airspeed Velocity Over a year ago

Using the [Type]() syntax for initialization when you’re supplying parameters looks kind of odd to me tbh. You could also try var threeDoubles2 = Array(count: 3, repeatedValue: nil as Double?) or var threeDoubles3: [Double?] = Array(count: 3, repeatedValue: nil) or var threeDoubles3 = Array<Double?>(count: 3, repeatedValue: nil).

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