How do I check in Swift if two arrays contain the same elements regardless of the order in which those elements appear in?

Question

Let\'s say there are two arrays...

var array1 = [\"a\", \"b\", \"c\"]
var array2 = [\"b\", \"c\", \"a\"]

I\'d like the result of the compar

Answer 1

Using Set

let array1 = ["a", "b", "c"]
let array2 = ["b", "c", "a", "c"]

let set1 = Set(array1)
let set2 = Set(array2)

if (set1.count == set2.count && set1 == set2) { //if you compare big sets it is recommended to compare the count of items in the sets beforehand
    //they are identical
}

The Set implements Hashable so the task is to implement the hash function to work with a Set

Answer 2

Swift 3, 4

extension Array where Element: Comparable {
    func containsSameElements(as other: [Element]) -> Bool {
        return self.count == other.count && self.sorted() == other.sorted()
    }
}

// usage
let a: [Int] = [1, 2, 3, 3, 3]
let b: [Int] = [1, 3, 3, 3, 2]
let c: [Int] = [1, 2, 2, 3, 3, 3]

print(a.containsSameElements(as: b)) // true
print(a.containsSameElements(as: c)) // false

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