Set of arrays in Swift2

Question

Hey I am trying to make a Set of Arrays and the arrays are to hold 2 integers

When I do

var points = Set<Array<Int>>();

I get this error:

Array<Int> does not conform to protocol hashable

I am trying to store a bunch of points like [x,y] ie. [33, 45] [x,y] ie. [33, 45]

I don't want to use a 2d array because the order of the points does not matter and I want to be able to remove points by their values ( Set.remove[33,45] )

Answer 1

Instead of using arrays in such case, try creating a struct :

struct Point: Hashable {
    var x: Int
    var y: Int

    var hashValue: Int {
        get {
            return (31 &* x) &+ y
        }
    }
}

// Hashable inherits from Equatable, so you need to implement ==
func ==(lhs: Point, rhs: Point) -> Bool { 
    return lhs.x == rhs.x && lhs.y == rhs.y
}

var set = Set<Point>()
set.insert(Point(x: 33, y: 45))
print(set.count) // prints 1
set.remove(Point(x: 33, y: 45))
print(set.count) // prints 0