How to create an Array for Tuples in Scala?

Question

Im trying to create an empty Array to store coordinates of an object in an Tuple which is then stored in an Array.

When I try:

var walls = Array[Tuple2]()

Im getting this error message:

kinds of the type arguments (Tuple2) do not conform to the expected kinds of the type parameters (type T).
[error] Tuple2's type parameters do not match type T's expected parameters:
[error] class Tuple2 has two type parameters, but type T has none
[error]         var walls = Array[Tuple2]()

Is there any possibility to do this?

You want something like `Array.empty[(Int, Int)]` or whatever type your coordinates will have. - also, you probably want to remove the two layers of mutability as well as avoid using `Arrays` — Luis Miguel Mejía Suárez, Feb 18 '23 at 15:13

score 4 · Answer 1 · answered Feb 18 '23 at 15:42

Tuple2 is a type constructor (of kind [*, *] => *).

Array is a type constructor too (of kind [*] => *).

You have to apply Tuple2 to two types (of kind *) in order to make it suitable as an argument of Array.

That's why Array[(Int, Int)] aka Array[Tuple2[Int, Int]] is working while Array[Tuple2] is not.

score 2 · Answer 2 · answered Feb 18 '23 at 15:14

2

Okay I found a way:

var walls = Array[(Int, Int)]()

answered Feb 18 '23 at 15:14

TamZ

27
3

How to create an Array for Tuples in Scala?

2 Answers2