Hello everyone, how can I create a data structure for example with two different types like ArrayList<Double, String>

this is likely a naive solution but in Java you could say

ArrayList<Object>

and cast them in and out... or create a class that has a property of either Double or String and have an

ArrayList<MyClass>

but as for Kotlin likely far better ways

You can also take a look at

Either

from either #funktionale or #kategory.

@stefano.maffullo Short answer is you can't in Kotlin, but a language like Ceylon can. In Kotlin, you'd create your own structure that contains all the types you need and discriminate on them (e.g.

Either

)

Yeah it's fine for me to create my own structure, so my own "structure" it's a Class/Object?

For example

data class MyStructure { val d: Double, val s: String }

and put that in your list

Thank you very much! Can I bother with another question? Is better a list of MyStructure or a 2D array?

As a general rule, avoid using arrays. So

ArrayList

.

So I'll use listOf<MyClass>

@cedric can I ask why you would suggest avoiding arrays?

The general reason is that arrays don't play nicely with generics, mostly because they predate them. This was already a rule of thumb in Java so it's not specific to Kotlin